On Broadway, Allen received a Tony Award for her performance opposite JohnMalkovich in Lanford Wilson's Burn This (1987), and was nominated inthe same category for The Heidi Chronicles (1989). Off-Broadway, shewon an Obie for her starring role in The Marriage of Bette & Boo. She reprised her Steppenwolf Theatre role in And A Nightingale Sang,receiving the Clarence Derwent, Drama Desk, Outer Critics Circle andTheatre World Awards.

In 1996, Allen dropped ten pounds to star opposite Anthony Hopkins in Oliver Stone'sNixon, where her eerily accurate portrayal of Pat Nixon won her anAcademy Award nomination for Best Supporting Actress. She received hersecond consecutive Best Supporting Actress nomination in 1997 for ArthurMiller's The Crucible, also featuring Daniel Day-Lewis and Winona Ryder.

In 1997, Allen starred in John Woo's thriller, Face/Off (1997), withJohn Travolta and Nicolas Cage, and in Ang Lee's poignant drama, The IceStorm, with Kevin Kline and Sigourney Weaver. In 1998, she appeared inPleasantville as Betty Parker, a June Cleaver-esque housewife whodiscovers her true self.

In 2001, Allen stars with Anjelica Huston in the television miniseries The Mists of Avalon, based on the bestselling novel about the women behind King Arthur.

Allen is married to actor Peter Friedman and has a daughter, Sadie. Shetravels back to her hometown of Rochelle, Illinois every summer to spendtime working with aspiring actors and actresses.