Vo filme Medvedie srdce hrajú Joaquin Phoenix (Kenai (voice)), Jeremy Suarez (Koda (voice)), Jason Raize (Denahi (voice)), Rick Moranis (Rutt (voice)), Dave Thomas (Tuke (voice)), D.B. Sweeney (Sitka (voice)), Joan Copeland (Tanana (voice)), Michael Clarke Duncan (Tug (voice)), Harold Gould (Old Denahi (voice)), Paul Christie (Ram #1 (voice)), Danny Mastrogiorgio (Ram #2 (voice)), Estelle Harris (Old Lady Bear (voice)), Greg Proops (Male Lover Bear (voice)), Pauley Perrette (Female Lover Bear (voice)), Bumper Robinson (Chipmunks (voice)), Darko Cesar (Foreign Croatian Bear (voice)), Angayuqaq Oscar Kawagley (Inuit Narrator (voice)), Sherry Lynn (Additional Voice (voice)), Mickie McGowan (Additional Voice (voice)), Debi Derryberry (Additional Voices (voice)), Patrick Pinney (Additional Voices (voice)).