Brandis began his entertainment career at age two appearing in a sales poster for Buster Brown clothing. By five, he was acting in TV ads for Kix cereal and Fisher-Price toys and played a recurring role on the daytime soap "One Life to Live" by age six. He moved with his family to L.A. at nine and soon found work in TV guest spots, pilots, and miniseries. Brandis segued to features as an "additional voice" for "Oliver & Company" (1988), a minor Disney animated effort. He was more visible as an imperiled youngster in the disappointing "Stepfather 2" (1989) and starred as a warrior youth in "Neverending Story II: The Next Chapter" (1990), another lackluster sequel, before gaining attention with "Ladybugs". Brandis was paired with Chuck Norris in the martial arts comedy "Sidekicks" (1993) the summer before submerging himself in "seaQuest". He hoped to bid juvenile roles farewell after starring in the TV-movie "Good King Wenceslas" (1994) and co-starring with Kellie Martin in "Her Last Chance" (NBC, 1996).

Although his billing and the prominence of his adult roles shrank in adulthood, the actor continued to work steadily. Brandis appeared in a supporting role as Mousy in director Michael Corrent's 1999 adaptation of filmmaker Peter Farrelly's novel "Outside Providence" (a less scatalogical offering from one of the Farrelly Brothers), and he was part of the supporting ensemble of Ang Lee's underrated Western "Ride With the Devil" (1999). His next major mainstream screen effort was as one of the army privates in the Bruce Willis military drama "Hart's War" (2000). Among his final film roles was "The Year That Trembled" (2002), independent filmmaker Jay Craven's adaptation of the Scott Lax coming-of-age novel set in Ohio after the shootings at Kent State University, which earned Brandid strong reviews among the cadre of critics who saw the film. In 2003 Brandis' death at age 27 was deemed a suicide; the actor was discovered unconscious after apparently hanging himself at his Los Angeles home.