- Voiced by: Cathy Weseluck
She has long blonde hair tied back into a ponytail by a purple thing, possibly a hairband or clip or scrunchie.
Her eyebrows are dark blonde or maybe even brown, while Fiona's are black.
She has blue eyes and facial freckles, like the blonde ponytail, also things which Fiona possesses, possibly indicating Coop and Dennis have similar aesthetic taste in women. The teacher's freckles are fewer though, 3 above her nose between her eyes, compared to Fiona who has 4 under each eye for 8 total.
She has a small round nose like Coop and Millie (Burt's is larger and more oblong) while Fiona's is pointy.
She has worn a dark red fully skirt (less pink skirt below) and possibly a white T-Shirt inside.
Season 1 is Age 45 and Season 2 is Age 46 when she's an adult
She first appeared in "Me-Oh Me-Oh Meow" when Coop was in school wearing Kat's Special collar on his leg in her class.
In "Curse of Tutankitty's Tomb" her last name was revealed when she was touring the class with Burt in a museum.
After a cafeteria food fight when Burt threw food into her face, she looked angry. She also reveals to teach math in "Dire Education".
In Coop D'Etat when she stops coming to school, being frazzled by he rambunctious class, she grabs a tub of strawberry frozen yogurt out of a supermarket freezer and begins eating her "comfort food" on the spot barehanded without even closing the freezer or paying for it. She seems embarrassed when Burt witnesses this (she squeezes the container so hard the yogurt spurts out) but accepts his invite to go canoe-fishing.
RelationshipsCurse of Tutankitty's Tomb" when Coop asked her he wanted to go to the bathroom and she allowed him (unaware Coop goes to stop Kat from releasing Tukankitty instead of going to the bathroom).
- In "Curse of Tutankitty's Tomb" she accidentally lets Burt take over the class for the class tour and she sits lonely on the bench and was annoyed with his actions
- In "Dire Education" when Burt stands on the desk dancing cheering his son Coop when Coop got 91 percent on his work. She stood Burt in the corner for interrupting her class and the class's parents once more which caused everyone (except Coop and Miss Brannigan) to laugh at Burt.
This pattern alters in season 2. In You, Kat See Me she makes an angry call to Burt about Coop's homework. When he comes in to talk to her as requested, she says it is the 49th time Coop used the excuse of Kat shredding his homework. When Burt tries to excuse it for an overactive imagination she condescendingly pushes him from standing back into a chair behind him out of the way while walking past him with her eyes closed.
When Burt identifies a mint-condition PlayMeister 4200 and states he is impressed while putting it on (without permission) her body language and demeanour change. She clasps her hands in front of her chest, her frown changes to close-lipped then open-lipped (tooth-bared but closed) smile, and she faces toward him while opening her eyes wide. She says "ooh" and purses her lips toward him before asking "really?" and brings her left hand to her chin.
She continues to smile as Burt leaps on her desk dancing to cassette tape music he hears on the earphones. When he jumps down and dances across the room, she catches him with her right arm when he falls. Their feet are offscreen when this happens so it is not clear if she intentionally tripped him or if he stumbled over her feet.
Burt grins up at her and while holding him, she laughs while bringing her left hand to her mouth. There is a scene cut at this point and then Burt comes out whistling. Before this, the clock is shown changing from 3 to about 3:10 to about 3:50-3:55, so they spent more than a half-hour off-screen.
Burt is still whistling after the drive home, leading Coop to ask himself out loud what they were talking about for "so long". Later when she arrives at the Burtonburger's House for dinner (it is unclear whose idea this was) Millie sniffs her right hand, remarking "you're right daddy, she does smell like rose petals" causing the teacher and Burt to blush and smile at one another. Burt chuckles and gently tells Millie that was supposed to be confidential.
Later Millie says "daddy was wondering if you have a boyfriend" (it is not clear if Burt said that or if Millie made it up) causing them both to laugh at smile at each other awkwardly. Burt interrupts this by dropping his spoon exclaiming "oops" and bending down to pick it up, breaking eye contact. Brannigan then turns her head away to eat, though she still keeps her eyes pointed at Millie and Burt's direction. She then frowns after seeing Fiona screaming through the yard and looking at the green stuff in her spoon. What causes her consternation is unclear.
Burt says they never got around to talking about Coop (probably meaning at dinner, since they had discussed him at school) and she says they could meet again later, at a restaurant. A specific date or place is not set though, as she is distracted by an invisible pink Fiona.
In the episode "Coop D'Etat", she tries to relax with Burt, after desist to give the class, because the kids make a very mess. They were fishing on a boat but when Burt holds out a worm to Miss Brannigan, she screams and makes the boat fall over and they held onto it while going down the stream. Their boat was smashed into the rocks, they were walking through the woods with bees buzzing around them and get chased by a bear. Later it was unknown they were falling off the cliff and they get rescued by a helicopter. Miss Brannigan returns to school and her class but she gives Coop detention for a month for the Science Center incidents thanks to Old Lady Munson and Kat.