[citation needed] Balsam began her career appearing in a recurring role on the ABC sitcom Happy Days and later appeared in a number of shows, including Dallas, Taxi, Hill Street Blues, Family Ties, The Larry Sanders Show, and Magnum, P.I.
[2] She also appeared in a number of made-for-television movies, including Kent State (1981), Nadia (1984), and Consenting Adult (1985).
Balsam continued playing supporting film roles and guest starred on television through 1990s and 2000s, include The Cake Eaters (2007), L.A. Doctors (1998–99) and Without a Trace (2003–04).
From 2007 to 2014, Balsam had a recurring role as Mona Sterling in the AMC period drama series Mad Men.
From 2016 to 2019, she starred opposite Sarah Jessica Parker in the HBO comedy series, Divorce.