Born Michelle Ann Marie Fabares in Santa Monica, California, she is the niece of Nanette Fabray. She got her big break in the role of the teenage daughter in the long-running television family sitcom, The Donna Reed Show. Her national popularity led to a recording contract and she had two "Top 40" hits including "Johnny Angel" that went to No. 1 on the Billboard Hot 100 in April of 1962. Fabares left the TV show for a career in film and starred in a number of motion pictures including three Elvis Presley movies: Girl Happy (1965), Spinout (1966) and Clambake (1967).

Fabares married Jan & Dean's record producer Lou Adler in June 1964 before separating in 1966. The couple would later officially divorce many years later, in 1980.

In later years she returned to television, most notably in the roles of Francine Webster on One Day at a Time and as Christine Armstrong Fox, on the sitcom, Coach.