He won a gold medal in the 1976 Summer Olympics and after graduating from the University of Michigan, played for the Detroit Pistons and Cleveland Cavaliers of the National Basketball Association (NBA) from 1979 to 1989.

Hubbard averaged 15.1 points and 11.0 rebounds, playing alongside Rickey Green as the Wolverines had the second-place finish at the 1976 NCAA Championship.

[4][2] In 88 career games at Michigan (1975–1979), Hubbard averaged a double-double of 16.5 points and 11.1 rebounds on 53% shooting from the floor and 63% from the line.

[9] On February 16, 1982, Hubbard was traded by the Detroit Pistons with Paul Mokeski, a 1982 1st round draft pick (John Bagley was later selected) and a 1982 2nd round draft pick (Dave Magley was later selected) to the Cleveland Cavaliers for Kenny Carr and Bill Laimbeer.

[12][11] In 2015, Hubbard was hired as an assistant coach for Jeonju KCC Egis in the Korean Basketball League in South Korea.