She is the daughter of director Boris Sagal and the stepdaughter of Marge Champion.
In the 1980s, Liz and Jean starred in the television series Double Trouble that ran from 1984 to 1985.
Sagal has since appeared on such shows as Knots Landing and Picket Fences.
She played a part in the film Howard the Duck, as a member of the fictional band "Cherry Bomb", in conjunction with which she contributed vocals to the songs "Hunger City", "Don't Turn Away (Reprise)", "It Don't Come Cheap" and "Howard the Duck".
Sagal has worked as a writer on such shows as Mad About You, Monk and Charmed, also serving as executive story editor on the last.