Acting and voice acting career
Summer's career began in 1983 when she was cast as the voice of niece Penny on the original cartoon version of Inspector Gadget. Her unique, throaty voice was instantly recognizable to casting agents (as well as viewers even today), who began frequently casting her in animated programs. Many of these were part of cult franchises, like The Care Bears Movie (1985) and Ewoks (1985, part of the Star Wars franchise).
Audiences finally had a chance to put Summer's voice to a face when she was cast as the freespirited Winifred "Freddie" Brooks in The Cosby Show spin-off A Different World. She remained a regular cast member of the show from 1988 through its end in 1993.
During the run of A Different World, Summer continued working in voice acting. She was cast in the short-lived television series Sweet Justice in 1994 until its cancellation in 1995. Barring guest appearances on other live-action television shows such as Living Single and The Fresh Prince of Bel-Air, Summer's professional work since has been limited to voice acting.
At the start of the series' third season in 1988, the cartoon series The Real Ghostbusters episodes were expanded from their original half-hour format to last an hour, and the overall feel of the show was changed to be more youthful, with episodes having a lighter tone to be less frightening (even switching artistic styles from more serious to less). During the less serious segments, Cree voiced the sweet and helpful Chilly Cooper, neighborhood ice-cream woman and innocent love interest of Slimer.
In all, Summer has voiced over 100 animated characters between 1983 and 2006. These have spanned the realm of video games, cartoon television series, animated films and commercials. Among her most famous roles was in Inspector Gadget (Season 1) as Penny (a role she reprised in the Robot Chicken episode "Adoption's an Option"), Tiny Toon Adventures (1990) as Elmyra Duff (which she reprised for Pinky, Elmyra & the Brain) and Mary Melody, Aka Pella in Histeria!, Susie Carmichael in Rugrats and its spin-off All Grown Up!, Cleo the Poodle in Clifford the Big Red Dog, Foxxy Love in Drawn Together, Dulcy the dragon in Sonic the Hedgehog, Princess 'Kida' Kidagakash for Disney's Atlantis: The Lost Empire, Valerie Gray in Danny Phantom (2004), Numbuh 5 (Abigail Lincoln) and Cree Lincoln in Codename: Kids Next Door, Penelope in Barbie As Rapunzel and Miranda from As Told by Ginger, Tiff on My Life as a Teenage Robot, octogenerian villain Granny May on WordGirl and Blackarachnia in Transformers Animated (2008).
Summer is also the voice of the Green spokescandy for M&M's.