His parents were divorced before he was born, and his mother, actress Sharon Thomas, married the film director Christopher Cain, who adopted Dean.
He was an honor student in high school and graduated from Princeton University, where he was also an All-American football star. After graduation he signed with the Buffalo Bills, but a pre-season injury prevented him from ever playing professionally.
As an actor his credits include Lois & Clark: the New Adventures of Superman, Beverly Hills, 90210, Life Goes On (Corky and the Dolphins), A Different World, Grapevine, Miracle Beach, and The Stone Boy.