Archer was born in Los Angeles, California, the daughter of actors Marjorie Lord and John Archer. Archer married William Davis in 1968 though the couple divorced in the mid 1970s. She then married Terry Jastrow in 1978. Archer has two sons, one from each marriage. She was nominated for a Best Supporting Actress Oscar as Beth Gallagher, the deceived, then violently protective mother of a six-year old daughter and wife of stalked philanderer Dan Gallagher (Michael Douglas), whose weekend tryst with psychopathic book editor Alex Forrest (Glenn Close) buys him more than he bargained for, in Adrian Lyne's 1987 blockbuster Fatal Attraction.

Archer, along with her husband Terry Jastrow, have been members of the Church of Scientology, since 1975. Between 1982 and 1986 Archer was a spokeswoman for Applied Scholastics, the literacy training organization sponsored by the Church of Scientology.

Her son Tommy Davis is the head of the Church of Scientology's Celebrity Centre International in Los Angeles, California.

In 1998, Archer and fellow entertainers Isaac Hayes, Chick Corea, and Haywood Nelson attended the 30th anniversary of Freedom Magazine, the Church of Scientology's investigative news journal, at the National Press Club in Washington, D.C.