Donaldson turned pro with the Dallas Black Hawks in 1971-72 and played there for four seasons, topping the 20 goal mark three times. In 1973-74 he was called up for his one and only NHL game with Chicago.
In 1976-77 he jumped to the Houston Aeros of the World Hockey Association. He only played five games for the Aeros, spending the rest of the season with the Oklahoma City Blazers. He retired at the end of that season.