He dislikes whiny students and hasn't been out on a Friday night since "1986." Though he’s incredibly unsatisfied with his job and is often trying to seek a new one, he wants to have a life-changing affect on his students. He teaches multiple subjects, as shown in different episodes, but mainly history and science (he’s also shown teaching math and Spanish). His lectures are so boring, he puts himself to sleep.
As frustrated as he is with his students from time to time, he still cares about them, and sometimes takes parental approaches to disciplining them, such as calling students by their full names when they are misbehaving ("Happy Birthfish, Jocktopus," "Brothers' Day," and "Milo and Oscar Move In"). He sometimes becomes empathetic with them, like when he associates Milo's declaration of Brothers' Day with his own desire to have one brother, rather than eight older sisters, in his youth. Even though he never knew he could get pregnant, he seems to have accepted it quite well, especially after revealing it to the class, and is even open about it from time to time.
He was first seen when he spotted Bea sneaking into Clamantha's locker so she could get her yearbook picture. When the "Grow-Dino" grew and exploded inside the locker, he simply said, "Works for me" ("Bea Stays in the Picture"). It is shown that Mr. Baldwin sleeps during his job. Mr. Baldwin does roll call every morning, and in the episode "Fish Out of Water", he can't stand Milo's entrance with the eel. Mr. Baldwin says it can't be about him all the time. He then reveals that he's pregnant and never even knew male seahorses could get pregnant ("Fish Out of Water"). He caught Jocktopus beating up Albert and called him by his full name. He then made Albert go to detention for standing in the hallway too long ("Happy Birthfish, Jocktopus").
When Mr. Baldwin did a lecture about Shellington and the battle of "Water-in-the-Loo," Milo was causing several distractions. When Baldwin could not take it anymore, he told Milo to see him after class. He put him in a bag full of water and told him he was failing class. Milo assumes he is joking, and heads off, leaving Baldwin annoyed and dumbfounded. When it was time to take the test, Mr. Baldwin noticed Milo wasn't in his desk. When Milo barely passed the test, Mr. Baldwin was as overjoyed as Milo, as he wouldn't have had to hold him back another year and "lose any more hair due to stress" ("Fail Fish").
Mr. Baldwin once took Oscar's backpack, and when he picked up his phone a moment later, he told his students he had "car trouble". Milo thought Baldwin was secretly Captain Aquarium, so he, Oscar, and Bea (who needed a story for journalism) spied on him to see if he was a superhero. At first, the book said Captain Aquarium saved the city from giant monsters, and Mr. Baldwin appeared to be doing it, until it revealed he was just getting new glasses. Afterwards, the book said Captain Aquarium fought criminals, but Baldwin ran away when he saw criminals at the bank. Lastly, it said Captain Aquarium changed his outfit in a phone booth, but Baldwin just napped there. Milo still didn't want to give up, so he came up with a plan. Bea led Mr. Baldwin to Oscar, who was dressed as a villain, and Milo trapped in a glass cup. Baldwin didn't fall for it and was about to take Milo and Oscar home, but when Bea flashed her camera, Mr. Baldwin accidentally let go of the cup. The gang escaped the sharks, as they were vegetarians, and Mr. Baldwin helped Bea pass journalism ("Baldwin the Super Fish").
Mr. Baldwin once did a drawing of a robot fighting a dinosaur on the board, but was interrupted by Albert's coughing. He then noticed Albert had the dropsy and hit a button, making Principal Stickler and Nurse Fishington come and put Albert in a bag ("Dropsy!"). When the Swirlies were about to come on, Mr. Baldwin wanted tickets and asked his students if they had any, even offering them an A for the semester. Albert stood up, but it just turned out to be his birthday and he was gonna hand out cupcakes ("Fishing For Compliments: The Albert Glass Story").
When Milo turned giant and smashed Mr. Baldwin's classroom's wall, Mr. Baldwin said "I'm not even gonna turn around," and continued drinking his coffee. When Milo turned extremely giant and tried to climb the tanks to Freshwater High, he passed Mr. Baldwin's apartment room. The moment Mr. Baldwin saw Milo, he froze in shock and his hair fell off ("Big Fish"). When Milo went out peopleing, Bea suggested Milo find some other cool role model. She suggested a fish teacher, and they saw Mr. Baldwin sucking algae off gravel ("Peopleing"). When Milo went crazy for recycling, he took off Mr. Baldwin's glasses while he was driving, causing his car to crash ("Legend of the Earth Troll").
When Milo asked Mr. Baldwin why male seahorses could get pregnant, Mr. Baldwin didn't respond ("Good Morning, Freshwater"). When Bud was cleaning the tank that included Freshwater High, Mr. Baldwin told everyone to escape, and threw Clamantha in the classroom afterwards to see if it was clear ("Diary of a Lost Fish"). When the class went on a field trip to Pupu Goodtimes Amusement Park, Mr. Baldwin was shown to hate chaperoning field trips, and told the students to bother him only if it was an emergency. When Mr. Baldwin was about to go on the Pu-Panator, the ride attendant told him that pregnant seahorses weren't allowed to ride ("Good Times at Pupu Goodtimes").
When Mr. Baldwin was taking attendance one, he came across a couple of student's name that started with an "O", and Oscar came to school just in time for his perfect attendance award ("Run, Oscar, Run"). Mr. Baldwin was shown to be really bored, and even slept at some points in the "Potatoes for Winter" play. When the play was over, Mr. Baldwin was still sleeping, eventually waking up, glad that the play was over ("Fish School Musical"). Mr. Baldwin gave Milo and Oscar all of his money for a hat so Milo and Oscar could stop begging him to do so. He then ran away from the store, screaming. At the dance, Baldwin gave Ms. Lips the hat that he bought, and said, "What a doll" when he was watching her skip into the school, showing his first hint at a crush on her ("Employee Discount").
When Mr. Baldwin got Steve Jackson's hair gel all over his hair, he showed it to Milo, Oscar, Albert, Jumbo, and Steve Jackson, but they seemed really disgusted by his hairstyle ("Hairanoid"). Bea and Milo delivered Mr. Baldwin's present to his house on Christmas, causing Baldwin to wake up the second they left thinking they were intruders ("Merry Fishmas, Milo").
In "Fish Lips Sink Ships", he reveals his crush on Ms. Lips to Milo, after he is caught rehearsing asking her out. His primary reason for never doing it before was out of paranoia that he would be rejected. While trying to stop Bea from revealing his crush to Ms. Lips, he finally works up the nerve to ask her out.
Mr. Baldwin and Ms. Lips are shown to be in a relationship after the episode "Fish Lips Sink Ships". In "Labor of Love", Mr. Baldwin follows Ms. Lips to Flip Flop Island, trying to work up the courage to ask her to marry him. With the help of Milo and Bea telling him what to say through a headset, he tries to ask Ms. Lips to marry him, failing when he accidentally calls her cat stupid because of Bea. Ms. Lips gets angry, and Mr. Baldwin tries to apologize, only burping because of his nausea. Ms. Lips smacks him, sending the engagement ring deep into the temple they were standing on. Later, Mr. Baldwin is shown depressed, eating lots of tacos. Milo and Bea get everyone together to try to set Ms. Lips and Mr. Baldwin up without Ms. Lips knowing until she sees him. They send Oscar, Jumbo Shrimp, and Albert after the ring. After Ms. Lips arrives at the restaurant Mr. Baldwin is at, she is at first disappointed he is there, but starts to become a little fonder of him after Milo and Bea put on a play about how Mr. Baldwin likes cats. After Bea accidentally calls Ms. Lips cat a "dumb furball", Ms. Lips starts walking away again. Mr. Baldwin stops Milo and Bea from creating a new plan, and decides to take matters into his own hands. He starts singing "Please Say You'll Stay", while Oscar, Jumbo, and Albert finally get the ring. The cat that was keeping the ring chases them, and they burst into the restaurant in the middle of the song, but Mr. Baldwin continues singing. He finally proposes to Ms. Lips when he catches the ring from Milo, and Ms. Lips is about to answer when Mr. Baldwin suddenly goes into labor. The cat that was chasing them calms down and tells Mr. Baldwin how to deliver his babies. After Mr. Baldwin tries and tries, he finally gives birth to about 100 to 200 offspring. Ms. Lips reveals afterwards that she will marry him, and they go home.
In "Assignment: Babies," tired from his duties as a new father, he pairs up the students in his class to babysit his children. At the end of the week, when he collects them, he seems unbothered by the fact that Bea and Oscar return empty-handed. It's made clear in this episode that he has so many babies, he doesn't notice when Baby Face Bryant somehow sneaks into his brood.
Later, in "Don't Let the Fish Drive the Party Bus," Milo gives Mr. Baldwin an invitation to his party, which he doesn't want to attend, implying he's far too busy caring for his children. Later in the episode, when Milo makes Ms. Lips think that it's the babies' idea for Baldwin to go to the party, she insists he should go. He does, very reluctantly, and at the end of the episode gets a concussion from the party bus crash, and the episode ends with Milo taking him to "Fish Urgent Care."
In "Freshwater Lives," Baldwin spends most of the episode trying to keep Milo from interfering in Ezekiel Freshwater's time capsule, stating that his father used to say "only a fool would mess with a time 'capsool'." After Freshwater is reanimated, Baldwin is unable to stop Milo from taking off with Freshwater, and instead lets him go and says "this won't be good" to himself. Sure enough, his "worst fear" comes true; Milo using a bulldozer to destroy Freshwater High.
In the series finale, "The Big Woo," he makes it known that he's (almost hysterically) happy to see his class graduating, though it's implied that's not exactly because he's "proud of them." He also says that students try to prank him every year at graduation and that it's "not cool." Milo interprets this (through a conversation with an imaginary tiny Baldwin) that Baldwin secretly wants to be pranked. Randy beats Milo to it, however, by getting the teacher to sit on a rubber chicken/whoopie cushion combo. In the end credits, Baldwin tricks Milo into thinking he's not graduating, before revealing that he was pranking him. Baldwin congratulates Milo on graduating before Milo runs back and pies him in the face.
Mr. Baldwin shows dislike towards Milo and doesn't generally like Milo's interest in him. He thinks of Milo as a "selfish fish" and also thinks it's annoying how Milo always interrupts the class when it's "learning time" ("Fish Out of Water", "Fail Fish"). As much as he is irritated with Milo, he cares about his welfare, and shows great concern for him (and himself) when he is failing the class, as well as making an effort to rescue him while falling from the edge of a shelf ("Baldwin the Super Fish"). He loses hair because of his stress teaching Milo, but in the past has confided in him about his problems with "the ladies" ("Fail Fish"). Milo also implies they've "shared a lot of laughs together," though Baldwin says he "stopped laughing in 1986." Still, he seems to trust Milo very much when he tells him about his crush on Ms. Lips ("Fish Lips Sink Ships"), though he was incredibly reluctant to tell him at first.
Milo always cares about Mr. Baldwin, and helps him when he needs a break or a hug, though Baldwin doesn't seem to like how often Milo tries to touch him ("Bea's Birthday Surprise," "Milo's Magical Shake"). He seems to be Milo's role model of sorts, though it's unclear how his fixation on Baldwin started or how long they've known each other. ("Fish Lips Sink Ships"); ("Labor of Love"); ("Hats Amore!"); ("Don't Let the Fish Drive the Party Bus").
Mr. Baldwin does tend to show a bit of care towards Milo in episodes like "The Big Woo", when he joyfully pranks Milo into thinking he didn't graduate, and seems genuinely proud of him graduating.
Bea is known for "interfering" in Mr. Baldwin's personal life, almost as much as Milo. She was very invested in getting Ms. Lips and Mr. Baldwin together, and her persistence is what got Baldwin to finally ask Ms. Lips out (before Bea could do it for him, "Fish Lips Sink Ships"). Bea also was convinced, mainly by Milo and Oscar, that Baldwin was a superhero. And despite Bea having the most common sense of the three of them, she did believe this strange rumor and was part of the plan to get Baldwin to reveal his superhero identity ("Baldwin the Super Fish").
It's implied that Baldwin thinks Bea is a talented singer, as her solo in "Fish School Musical" seemed to be the only part of the musical he actively enjoyed, though he pretends to not be impressed. But he also thinks her play in "Labor of Love" is the "weirdest play (he's) ever seen" and a "mess." But he ends the episode thanking Bea and Milo for their involvement in the proposal, though when Milo mentions planning the wedding, he also says "oh please no!"
Baldwin doesn't appreciate when Bea sleeps in class if he cannot "Milo and Oscar Move In," or when she is caught using her cellphone in class and detention ("Brothers' Day," "Pool Party Panic."). Bea also tends to not get away with as much as Milo or Oscar, as in "Brothers Day" or "Glass Man Standing." He uses her full name when he's angry, and sometimes calls her "missy." Though he seems skeptical about Bea becoming principal, he (and the rest of the faculty) give her their full support after she says they'll get raises ("Principal Bea").
Mr. Baldwin is seen standing, smiling, and clapping at the end of Bea's graduation speech in "The Big Woo," and it can be assumed that he's also proud of her graduating.
As a teacher, Mr. Baldwin interacts with all of his students at any given time. Albert has a lot of encounters with him, such as Baldwin punishing him for loitering in the halls where someone is "bound to punch him" ("Happy Birthfish, Jocktopus"), Baldwin getting excited thinking Albert has Swirlies tickets and calling him a "little genius" before begrudgingly taking a cupcake when it's just Albert's birthday ("Fishing for Compliments: The Albert Glass Story"), and calling him and Esmargot out for not dancing at prom ("Fish Prom"). He also becomes very alarmed when Albert is sick in "Dropsy!," though that may be more fear of contagion.
Jocktopus is the source of a lot of Baldwin's ire, and Mr. Baldwin will call him by his full name when angry. And he often tries to keep Jocktopus and Piranhica from showing public displays of affection in school ("Fish Prom").
He seems to like Koi, though he's not always able to read her body language ("Pool Party Panic"). But he joins in everyone else's admiration of her in "Koi Story" when everyone thinks she's done something dangerous, and asks to be included in her adventures because he "needs a little spice in (his) life."
Despite him being one of the main three characters, Oscar and Mr. Baldwin don’t interact all that much. And when they do it’s usually in direct correlation to something Milo is doing. Baldwin does generally appear happy for Oscar winning the Perfect Attendance award (“Run, Oscar, Run”), and Oscar makes an effort to keep Baldwin’s crush a secret (as it reminds him of his own crush on Bea), as well as going into the temple with Albert and Jumbo to find Baldwin’s engagement ring.
Mr. Baldwin seems to understand that the students see Steve Jackson as being popular and attractive, though he gets a "serious glare" from how radiant Steve is in "Pool Party Panic." He also seems confused by the existence of Steve Mahalo on Flip Flop Island ("Labor of Love").
Randy appears to be one of Baldwin’s least favorite students. The crab is often playing pranks on him, including the one in the series finale, and he told Baldwin in “Spoiler Alert” that his babies were “all girls,” ruining the implied surprise of their genders. (This was mainly a cut-away gag, and did not impact the actual plot-line of Baldwin’s pregnancy).
It's implied he finds Esmargot a little bit gross ("Pool Party Panic").
He reacts to Clamantha with the general disdain that everyone else has for her.
Lulu Latoya Lips and Mr. Baldwin begin officially dating in "Fish Lips Sink Ships," however their first date in the timeline of the show is actually in "Employee Discount," in which they attend a school dance together. Baldwin buys her a hat from the store Milo and Oscar are working at, and although her head tears a hole in it (and she crashes through the school doors), he still calls her "a doll." It's rumored in "Fish Lips" that he's had a crush on her since 1986, but this is neither denied nor confirmed by either teacher. It's clear he has deep feelings towards her, but sees himself as inadequate in comparison (and is convinced she'll reject his advances), and struggles to even make casual conversation with her initially ("Fish Lips").
It's never stated how long they date, or even if they live together ("Don't Let the Fish Drive the Party Bus"), but after Baldwin proposes, it's implied that Ms. Lips is intended to be the mother of his children, and that she's always wanted "just tons of kids" ("Labor of Love"). In "Labor of Love," it's also discovered that Lulu has a pet-name for him, "Cupcake," which she accidentally calls him in front of his whole class. She also later calls him "baby" in the same episode when she's coaching him through his delivery. It's also never really shown how much or how little Ms. Lips assists in the raising of his children, as he's usually shown caring for the babies alone ("Don't Let the Fish Drive the Party Bus," "Assignment: Babies," "Bea Saves a Tree"). Although in "Party Bus," she does refer to the kids as "our babies."
It's made clear in "Labor of Love" (as well as most of the series in general) that Ms. Lips is very protective of Attila, and may even value her relationship with her cat above all other relationships. If she feels her cat has been disrespected, she is not happy. When she believes that Baldwin hates Attila, slaps him and dumps him on the spot. Later in the episode, it's implied she can't tell between reality and Bea's play when Bea (dressed as Baldwin) calls Attila a "dumb furball," which enrages her. But after Baldwin apologizes and proposes, it's assumed she forgives him.
Ms. Lips also finds Baldwin's dating video from 1986 when she's watching videos on "FishTube" ("Surfing the Interwet"), and realizes that it's something he probably wouldn't want her to see, but watches it anyway.
In "Hats Amore!," the last episode that puts emphasis on their relationship, Mr. Baldwin puts a great importance on getting Ms. Lips parents to like him and know that they "really care about each other." He goes so far as to let Milo convince him to join the seahorse races. Only after he comes in last place with a tail blowout does Ms. Lips explain that he's "first in (her) heart" and that her parents only say "we don't like him" because they don't speak English and that's the only phrase they know. But she tells him they think he's "pretty cool," to which he responds "I love ya', Lulu Lips!"
In "Labor of Love," Mr. Baldwin finally gives birth to between "100 to 200" babies (according to Jumbo), though the official number is never made clear. The most babies that have appeared together in one scene is on the plane at the end of "Labor of Love," which was about 39 infants. The least amount shown in a group is about 6 to 8. The babies have light green skin, and either have Baldwin's blue hair or brown hair (implying that the biological mother had brown hair), with the exception of a shot in "Bea Saves a Tree," in which some of them have pink or teal hair.
It's made clear throughout the series that Baldwin does not enjoy being pregnant, and that the pregnancy was likely unplanned, but there are several little subtle hints that he actually wants to be a dad. Mainly with the décor on his car, the crib seen in "Baldwin the Super Fish," and that he talks to them before they're born, although more in a moment of terror ("Unfinished Doll Business").
After they are born, he's shown to be extremely tired caring for them ("Assignment: Babies," "Don't Let the Fish Drive the Party Bus"), but also not reluctant to take them back after the class babysits, as he "kinda missed 'em." Though not ever shown to be overly-affectionate with his kids, he also doesn't seem to find parenting them entirely a chore. It can be assumed that some time passes between the events in "Labor of Love" and "Assignment: Babies," as the babies have a few teeth and are shown eating baby food instead of just milk.
- He is voiced by Dana Snyder, who also voices Bud and Clamantha`s Mom.
- He often sleeps on the job.
- It can be inferred that he's severely nearsighted without his glasses, as he cannot drive his car without them. ("Legend of the Earth Troll")
- Mr. Baldwin's first name was never revealed at any point in the series.
- His age is also never given, although it can be assumed he's older than 29 ("Bea Becomes an Adult Fish"), and likely "middle aged" ("Hats Amore!," "Baldwin the Super Fish").
- He gave birth to one hundred to two hundred children (both sexes) in "Labor of Love", instead of the quadruplet girls mentioned in "Spoiler Alert".
- He never knew that male seahorses could get pregnant until it happened to him ("Fish Out of Water"). How he didn't know this is unclear, seeing as he himself has a father who was present in his life (or implied to be)/("Freshwater Lives"), presumably also a seahorse, and this is one of the most known facts about seahorse biology. (He's not young, either, so how he's gone through his whole life not knowing this is very bizarre.)
- The biological mother of his children was never revealed. It was also never revealed how he got pregnant in the first place, as he mentions many times his social life is basically nonexistent.
- Seems to be a fan of the Swirly Derbies, and goes to extreme lengths to get tickets to the bout. ("Fishing for Compliments: The Albert Glass Story")
- He's a player of "Mazes & Magic" (more or less Dungeons & Dragons) and has played with Coach Salmons, Mr. Mussels, and Dr. Frog. Each of them being named after US presidents, with the exception of Baldwin himself using the character name The Zombie King (apparently because he fell asleep a lot during game campaigns). He keeps a set of dice under his tie. He requires his students to wash his car in real life before giving them a quest item. ("Hare and Back Again")
- In “Koi Story,” and only this episode, Baldwin is shown to have a Teaching Assistant (TA) named Evan, who is a bird. The two of them are involved in all of the events of this episode.
- In 1986, he, Coach Salmons, and Mr. Mussles all had (supremely awkward) dating videos made. It's implied they all knew each other at the time, but it may have been a weird coincidence. ("Surfing the Interwet")
- He attended Freshwater High, as did many of the other teachers. ("Get a Yob!")
- He's shown in a flashback to when Oscar was much younger, but Baldwin was still his teacher. Baldwin in the flashback has a full head of hair and is not pregnant. So this is either supposed to be Oscar's freshman year, or Baldwin once taught middle school. ("Science Fair Detective Mystery")
- He enjoys drawing on the chalkboard, and often shows off his art to his class.
- He has a "Baby Aboard!" sign on his car (parody of Baby Onboard car tags).
- It's implied he's not very financially secure, as he lives in a very poor apartment complex and his car is rather old.
- His car license plate is "PREGDAD1" ("Legend of the Earth Troll").
- He also has a Mickey Mouse antenna topper ("Baldwin the Super Fish").
- Refers to 8 older sisters ("Brothers' Day"), and a father ("Freshwater Lives"), none of whom have names nor are ever seen.
- He has a best friend named Mark, who has never appeared in any episode of the series ("Dropsy!").
- Milo said during his class that his nose looks like a giant sea cucumber ("Fish Sleepover Party").
- He has a "Panic Button" in both his classroom and his apartment. ("Dropsy!" & "Baldwin the Super Fish")
- Mr. Baldwin hasn't been out of his house on a Friday night since 1986 ("Baldwin the Super Fish").
- He has a very strict "no sleeping in class if he doesn't get to" policy ("Milo and Oscar Move In").
- He deals with such pregnancy side effects as fatigue, indigestion, increased appetite, and frequent urination.
- Mr. Baldwin's Fishbook profile