The "Free Willy" actor was under hospice care when he died Thursday, The Dallas Morning News reported Friday.
Schellenberg was born in Montreal and was of Mohawk and Swiss-German descent, and frequently played American-Indian characters, including Sitting Bull in HBO's 2007 production of "Bury My Heart at Wounded Knee," the newspaper said. That role earned him an Emmy nomination.
Schellenberg began his career as a stage actor, winning the Tyrone Guthrie Award for most promising young actor at the Stratford Festival in Ontario, his son-in-law, Adrian Churchill said.
"He did a lot of stage work at the early part of his career and then in his 40s he started doing a lot more film work," Churchill said. "His first big film -- with a great deal of international success -- was 'Black Robe.'"