Kathleen Quinlan was born on November 19, 1954, in Pasadena, California, to Josephine Zachry, a military supply supervisor, and Robert Quinlan, a television sports director. Raised in Mill Valley, California, she attended Tamalpais High School where she studied drama and participated in gymnastics and diving.

Her athletic background led to her being cast as a stunt double in her early career.

Her official film debut came in George Lucas's 1973 movie "American Graffiti," where she played a minor role. She gained critical acclaim for her role as Deborah Blake, a sixteen-year-old schizophrenic, in the 1977 film "I Never Promised You a Rose Garden," earning a Golden Globe nomination for Best Actress in a Motion Picture - Drama.

Her portrayal of Marilyn Lovell, the wife of astronaut Jim Lovell, in the 1995 film "Apollo 13" earned her both a Golden Globe and an Academy Award nomination for Best Supporting Actress.

Kathleen Quinlan appeared in numerous feature films, including "Lifeguard" (1976), "Airport '77" (1977), "The Promise" (1979), "Twilight Zone: The Movie" (1983), and "Clara's Heart" (1988).

She also starred in several TV movies and series, such as "Family Law" (1999) and "Chicago Fire" (2012-2013).

Kathleen Quinlan was married to actor Warren Long in 1987, but the marriage ended the same year. She later married Bruce Abbott in 1994, and they had a son, Tyler Quinlan Abbott, before divorcing in 2022.