Casey MacDonald
Casey MacDonald
Gender Female
Age 23 or 24
Birthday c. 1990
Hometown Canada
Profession N/A
Family & Friends
Parents Mother, Step-father
Siblings Derek, Edwin

Marti, Lizzie

Spouse N/A
Children N/A
Friends Emily
Frenemies N/A
Enemies N/A
Pet(s) N/A
Production Information
First appearance The Room
Portrayed by Ashley Leggat

Casey McDonald (born in 1990) is a fictional character from the Canadian TV series Life with Derek. She was played by Ashley Leggat.

Character description

Casey is a smart and well-mannered teenage girl who claims to have once had a perfect life, living with her single mother Nora and her little sister Lizzie. When her mother meets and marries a lawyer named George Venturi, who happens to have three kids of his own, she is forced to move, change schools, and adjust to living with her "what Derek wants Derek gets" stepbrother. Although Casey is very opinionated about Derek being sneaky and cruel, she herself can be selfish at times. As the series progresses, Derek starts to rub off on her.

She enjoys controlling his band 'D-Rock' as the only lead singer, and loves to mock him about him failing his driving test 5 times before he gets his drivers liscence. Her only constant is her self-righteousness, and she often needs the school counselor to set her straight. After Casey broke up with Sam, Casey had a crush on Max, and in "It's Our Party", at the end of the episode she is seen dancing with him. Afterward, the two start dating. Casey is passionate about dancing, and she likes to sing, act, and her style is described as "preppy". Her best friend is Emily Davis. Casey is a perfectionist. If things aren't perfect, she often throws a fit.

In many episodes, Casey gets angry with her boyfriend Max if he makes even one mistake. She dated Derek's best friend Sam, but they break up, get back together and then break up once again which they then decide will be the last. They decided to remain friends, however. Casey and Max broke up in "Rumor Mill", but then they got back together at the dance in "Rumor Mill". They broke up again in "Allergy Season". On her Sweet 16 Casey had to have an emergency Appendectomy. While Casey was recovering from Appendicitis she threatend to put Derek in the hospital when she was fully recovered. Casey has hurt Derek's feelings a few times and she clearly didn't care. Casey got her driver's license before Derek, made fun of him because of it, and made him pay the car insurance for one year, and she made the cheerleading squad and as a bonus, it made Max's jealous ex-girlfriend Amy more friendly toward her.


  • Lizzie McDonald - (Jordan Todosey) Youngest of MacDonalds, but also the middle child in the house with Edwin and all the Macdonald-Venturies. Lizzie's a tomboy and is good at dancing and rapping.
  • Marti Venturi - (Ariel Waller) The youngest of Venturi children, and the Macdonald-Venturies. Marti's weird and she collects odd things. Marti and Derek are very close. Marti's nickname for Derek is Smerek.
  • Edwin Venturi - (Daniel Magder) The middle child, along with Lizzie, and has the worst of luck. Edwin often does Derek's bidding. Like Lizzie, Edwin's good at rapping.
  • Derek Venturi - (Michael Seater) Casey's popular, girl-crazy, and conniving step-brother. He and Casey often bicker and get into many an argument. Although Derek is portrayed as uncaring and lacking in brotherly instincts, he is very kind to his youngest sister, Marti. Derek's nickname for Marti is Smarti

Other people in Casey's life

  • Emily Davis - (Shadia Simmons) Casey's best friend and next door neighbor who has a major crush on Derek. She seems to think popularity is more important than her friends, but is always there when Casey needs her. She has a little brother named Dimmy who is friends with Marti.
  • Sam - (Kit Weyman) Derek's best friend who has a crush on Casey but is constantly being influenced by Derek. Casey also has a crush on Sam. In the episode "Male Code Blue" they finally decide to go steady, but break up in the episode "Middle Man-ic". He is one of the guitarists in the band, D-Rock.
  • Mr. Paul Greeby - (Arnold Pinnock) Casey's laid-back Guidance Counselor who is always ready to give Casey advice. Although Casey has asked him, he won't tell her what to do, only give suggestions. He is also very clumsy. Once, when tipping his chair back to far, he fell and landed in the trash can. He is also very disorganized, and is also the computer/science teacher in addition to being Guidance Counseler.
  • Max - (Robbie Amell) Casey's current ex-boyfriend. He is a jock, being quarterback of the school football team. He is revealed to be quite impolite sometimes, for example: not giving warning to Casey when a ball was about to hit her, not holding the door open for her, and laughing at Casey's embarrassing moments. But after Casey talks to him, he becomes more chivalrous. Casey and Max break up at the end of Allergy Season because Casey needed a break from her and Max just to figure out what was causing her allergies.

Relationships with other characters

Derek Venturi

While Casey has a lot to deal with in her life - living with George, Edwin, and Marti; trying to fit in at a new school; and figuring out where she and her sister stand in this new family; it all pales in comparison to her single biggest challenge, the show's namesake. "Life with Derek." She doesn't hate Derek,- she just didn't want to leave her old life and cram into his house. Everyone in the Venturi house has always been expected to play by Derek's rules, and Casey doesn't like that. While Casey is sneakier than she portrays herself to be, her "good person" side will come out if she really believes Derek needs her help, whether he really needs help ("Grade-Point: Average") or he's pretending to get his own way ("The Party") or somewhere in between ("The Wedding"). In the episode "Prank Wars", Casey is very concerned for Derek and fights against the principal for him not to be expelled. But Derek also cares about Casey, as shown in "Crushing the Coach." where Derek goes out of his way to prove to Casey that her new boyfriend is a jerk. At times, Derek can be a true friend to Casey, and save her from dangerous situations.

Lizzie McDonald

Casey uses Lizzie in much the same way that Derek uses Edwin, but Lizzie's much more loyal than Edwin. When Casey wants Lizzie to do something unethical or "mean" to beat Derek, she has to badger her into it. While the sisters have very different interests, they share a general appreciation for organization and femininity, although Lizzie isn't as passionate about it as Casey would like. They are very close.

Although Casey loves Lizzie, they are the opposite of each other. Casey is some-what girly and doesn't enjoy sports, Lizzie is tomboy-ish and enjoys sports, like soccer and hockey. And to Casey's dismay, Lizzie likes Derek and kind of enjoys living with the Venturis, although when Casey's around, she pretends to hate it. Even though Casey controls Lizzie like Derek controls Edwin, she is rarely mean and never violent. Lizzie admits herself that Casey is "usually a great sister."

Marti Venturi

Casey has mixed feelings about Marti - on one hand, she's a cute little kid, the most tolerable of the Venturis in Casey's eyes, and she really likes Casey. On the other hand, she's a Venturi, and a weak one at that, making her the quickest possible route to the takedown of Derek. Casey is always an excellent babysitter for Marti - she feels a little sorry for Marti since she grew up in a house of guys. Casey and Marti have a good relationship.

As seen in "House of Games" Marti didn't like Casey because she stepped on her imaginary friend Daphne, and quote, "Too late she hates you". Marti later forgives Casey though and loves her like a big sister. Through-out the series Marti starts to act older. Though she is only 6 and almost 7, she still tries to prove to Casey she is smarter than what she seems at times.