Mary Steenburgen portrayed Clara Clayton in Back to the Future Part III. She also provided the voice of Clara in Back to the Future: The Animated Series in addition to voicing her mother, Martha O'Brien.
She was born on February 8, 1953, in Newport, Arkansas. According to the commentary on the DVD for Part III, her children were fans of Back to the Future, and she readily accepted when cast for the role of Clara. Steenburgen's film debut was in the 1978 Western/comedy Goin' South, which starred Jack Nicholson and Christopher Lloyd. She starred with Lloyd again in the 2002 film Wish You Were Dead.
Back to the Future Part III was Steenburgen's second time-travel film. In 1979's Time After Time, she played the role of a 20th century woman who falls in love with a visitor from the 19th century (Malcolm McDowell as H.G. Wells).