Parker is the last of four children born to Stephen Parker, an aspiring writer, and Barbara, an elementary schoolteacher.
Parker's parents divorce when she's a toddler, and her mother remarries Paul Forste, a truck driver. They have four more children and move the family to Cincinnati, where they occasionally spend time on welfare. Despite the hard times, Barbara enrolls her children in scholarship-funded ballet, music and theater classes.
Forste takes Parker and her siblings to New York City to audition for the Broadway play The Innocents. Parker and her brother Timothy both land roles, prompting the family to relocate to New York, and Parker is enrolled at Manhattan's Professional Children's School. Three years later, she lands the title role of the spunky redhead in the Broadway production of Annie. She is the third actress to play Little Orphan Annie on Broadway.
Parker is cast as one of the two lead roles in the sitcom Square Pegs. She plays quirky high-schooler Patty Greene. Despite critical praise, the show is cancelled after one season.
Parker transitions to film in Footloose, playing Chris Penn's girlfriend Rusty. This is the first of a few roles Parker takes as the skinny sidekick with frizzy hair in the '80s. She tells In Style she felt she was "not pretty enough to play the lead." In 1985, she lands her first lead role in Girls Just Want to Have Fun, as Janey Glenn, a sheltered underdog competing against a stuck-up rich girl for a dancing spot on local TV show.
Parker meets her first love, Robert Downey Jr., when working alongside the troubled actor on the film Firstborn. She begins dating Downey – who was battling an alcohol and cocaine addiction – and decides to move in with him that same year.
After a string of television appearances and made-for-TV movies, Parker lands her breakthrough role as Steve Martin's bubbly lover, SanDeE*, in the comedy L.A. Story. "I had never played that [type] before, and it changed [producers'] perceptions about me," Parker tells the Chicago Tribune.
After seven years together and repeated efforts to help Downey kick his drug habit, Parker calls it quits. She tells Redbook, "I just found his [drug use] incredibly difficult to deal with." Downey tells Playboy that his substance abuse "was just confounding for her. But... there was a surprisingly high percentage of normal days as well. I love her and I always will." Afterward, Parker shoots Honeymoon in Vegas opposite Nicolas Cage, playing his voluptuous bride. She has a brief onset romance with Cage and also briefly dates John F. Kennedy Jr.
After these short-lived romances, Parker meets actor Matthew Broderick at an off-Broadway play he directs, starring her brother Toby. The two begin dating. She says to the Los Angeles Times, "He's probably the funniest fellow I've met in my entire life. I'm mad for him, totally."
Parker lands a starring role as a neurotic advertising copywriter in director David Frankel's Miami Rhapsody with Antonio Banderas and Mia Farrow. Frankel, a friend of Parker, says the actress grew up playing the ugly duckling. "For many years she was always surprised whenever she or a character she played was considered sexy," he says to PEOPLE. She also stars opposite Woody Allen in the filmmaker's TV movie The Sunshine Boys.
BIOGRAPHY (top to bottom): BIG PICTURES; LYNN GOLDSMITH/CORBIS; CBS; Kobal Collection/Wireimage; Barry King/WireImage; TriStar Pictures/Everett; PHOTOFEST; Kobal Collection/Wireimage