He was trained by animal trainers Doug (b. October 8, 1942, in Erie, Pennsylvania) and Lynne Seus (née Lynda Beers on March 27, 1944, in Lincoln, Nebraska) of Wasatch Rocky Mountain Wildlife, Inc., in Heber City, Utah.

[3] Robert Redford, Morgan Freeman, John Candy, Dan Aykroyd, Daryl Hannah, Annette Bening, Ethan Hawke, Steven Seagal, Tchéky Karyo, Brad Pitt, Alec Baldwin, Trevor Howard, and Anthony Hopkins all appeared in films opposite Bart,[5] and all were reportedly impressed with how well he was trained.

[5] Film critic Kenneth Turan called Bart's performance in The Edge "the capstone of an illustrious career" and "a milestone in ursine acting".

[7] Bart's greatest recognition came when he starred in the title role of Jean-Jacques Annaud's 1988 French film, The Bear, playing an adult grizzly who befriends an orphaned cub and defeats hunters.

In order to perform the role, Bart, trained by Seus, successfully learned several new routines and behaviors, including going against his natural abhorrence of a strange bear to accept the unrelated cub co-starring with him.

[10][12] Bart was a "spokesbear" for the Vital Ground Foundation, a nonprofit conservation organization that works to preserve threatened wildlife habitat along the Rocky Mountains and on Kodiak Island, among other places in North America.