Cartwright has also appeared in live action, including Joe Dante's segment of Twilight Zone: The Movie, a guest appearance on Cheers, the Made-for-TV Movie Marian Rose White, and the first American Godzilla movie (which also featured her Simpsons co-stars Hank Azaria and Harry Shearer), as well as making a guest appearance on an episode of 24 (the same season, stars Kiefer Sutherland and Mary Lynn Rajskub returned the favor by reprising their roles from 24 for a guest appearance on The Simpsons). Originally, she was going to do voice work on South Park, but turned it down due to its vulgar content. She even was a celebrity guest on Tom Bergeron's The Hollywood Squares and Donny Osmond's Pyramid.
Outside show business, Cartwright is a prominent member of the Church of Scientology.
Cartwright has done character voices for the following works:
- Richie Rich (1980): Gloria Glad
- Shirt Tales: Kip Kangaroo (season 2 only)
- The Snorks: Daffney Gilphin
- Popeye and Son: Woody
- Saturday Supercade: Kimberly (season 2 only, in "Space Ace" segments)
- Galaxy High: "Flat" Freddy Fender, Gilda Gossip
- Animaniacs: Mindy, additional voices
- The Simpsons: Bart Simpson, Ralph Wiggum, Nelson Muntz, Kearney (the bully who looks like a teenager, but isn't), Todd Flanders, and any one-shot boy characters.
- Cartwright also provides vocal effects (mostly cooing, laughing and crying) for Maggie Simpson and was the replacement voice for Elizabeth Taylor when the season 13 episode of The Simpsons showed a clip from season 4's "Lisa's First Word", where Maggie finally says her first word "Daddy" after Homer wishes that she never speak.
- Rugrats: Chuckie Finster (season 8 onward)
- Goof Troop: Pistol Pete
- The Critic: Margo Shermannote , various
- Kim Possible: Rufus
- The Replacements: Todd Daring
- Mike, Lu & Og: Princess Lu
- Putt-Putt: Putt-Putt (Enters the Race, Joins the Circus, and One-Stop Fun Shop only)
- My Little Pony: The Movie (1986) and My Little Pony 'n Friends: Gusty the unicorn, Posey the earth pony, Truly the earth pony
- Pound Puppies (1980s): Bright Eyes
- Bonkers: Fawn Deer
- Toonsylvania: Melissa Screetch
- Fantastic Max: FX