Born Michael Andrew Fox in Edmonton, Alberta, Canada, he adopted the "J" as an homage to character actor Michael J. Pollard. Moving several times during the course of his childhood, Michael and his family settled in Burnaby, a suburb of Vancouver. At the age of 15 he made his professional acting debut in the situation comedy "Leo and Me" (1981).
Moving to Los Angeles at the age of 18, Fox appeared in several small parts and a television series, "Palmerstown, U.S.A." (1980), before landing the role that would bring him to prominence in "Family Ties" (1982). Some of his other films include Bright Lights, Big City (1988), The Hard Way (1991), Light of Day (1987), Doc Hollywood (1991) and the three "Back to the Future" films.