Parker made her Broadway debut at the age of 11 in the 1976 revival of The Innocents, before going on to star in the title role of the Broadway musical Annie in 1979. Story (1991), Honeymoon in Vegas (1992), Hocus Pocus (1993), Ed Wood (1994), The First Wives Club (1996), The Family Stone (2005), Failure to Launch (2006), and Did You Hear About the Morgans? In 2012, Parker returned to television for the first time since Sex and the City, portraying Isabelle Wright in three episodes of the FOX series Glee.
She appeared in the 1984 films Footloose and Firstborn, and returned to Broadway in the 1989 play The Heidi Chronicles. She is currently starring as Frances Dufresne in the HBO series Divorce (2016–present), for which she was nominated for a Golden Globe Award.
She was selected for a role in the new 1977–81 Broadway musical Annie: first in the small role of "July" and then succeeding Andrea Mc Ardle and Shelley Bruce in the lead role of the Depression-era orphan, beginning March 1979. In 1982, Parker was cast as the co-lead of the CBS sitcom Square Pegs.
In 1997, she appeared as Francesca Lanfield, a washed-up former child actress, in the comedy 'Til There Was You.In the three years that followed, she was cast in four films: the most significant being Footloose in 19's Girls Just Wanna Have Fun, co-starring Helen Hunt.In 1986, Parker appeared in Flight of the Navigator, a Disney science fiction film.In 1977, the family moved to the newly opened planned community on Roosevelt Island, in the East River between Manhattan and Queens, and later to Manhattan.The family later moved to Englewood, New Jersey, where Parker attended Dwight Morrow High School.