In 2024, Light won the Primetime Emmy Award for Outstanding Guest Actress in a Comedy Series for Poker Face.

She again received Primetime Emmy and Critics' Choice Award nominations for playing Marilyn Miglin in The Assassination of Gianni Versace: American Crime Story in 2018.

In 2012 and 2013, she won two consecutive Tony Awards for Best Featured Actress in a Play, for her performances in Other Desert Cities and The Assembled Parties.

[3] In 1977, her agent phoned Light to have her audition for an understudy role in the ABC soap opera One Life to Live.

On trial, Karen saved her friend Viki Lord Riley (Erika Slezak) from being convicted of killing Karen's pimp, Marco Dane (Gerald Anthony) by admitting to the entire town, including her faithful husband, Dr Larry Wolek (Michael Storm), that she had been a prostitute.

Light's portrayal of Karen brought the show critical acclaim and is credited with garnering One Life to Live ratings successes from the late 1970s into the early 1980s.

[5][6] Light's dramatic, confessional courtroom performance of a housewife-turned-prostitute on the witness stand is regarded as one of the most memorable moments in television by TV Guide.

[7] In 1980, this won Light her first Daytime Emmy Award for Outstanding Lead Actress in a Drama Series;[8] the scene in which she confessed her guilt in court is held in such high esteem that it is still used in acting classes.

Elsewhere in its first season, called "Dog Day Hospital", in which she played a housewife who became pregnant for the ninth time even though her husband claimed he had had a vasectomy.

After her success on daytime television, Light landed the leading role of assertive advertising executive Angela Bower on the ABC sitcom Who's the Boss?.

[1] She spent most of the 1990s starring in made-for-TV and feature films including Men Don't Tell and 1997's Too Close to Home, which co-starred Ricky Schroder.

She earned strong reviews for her portrayal of Vivian Bearing, a university professor battling ovarian cancer, and reprised the role for the national tour.

[12] Light returned to television with the recurring role of Judge Elizabeth Donnelly in the NBC legal crime drama Law & Order: Special Victims Unit in 2002.

[14] In 2006, Light joined the cast of the ABC comedy-drama series Ugly Betty as Claire Meade, the mother of Alexis and Daniel.

She co-starred opposite Chris Messina and Jennifer Westfeldt in the 2006 romantic comedy film Ira & Abby.

[15] Light's character, Gayle, runs a Christian ministry known as Genesis House, which works to help gay men recover from their 'affliction.'

The New York Times said in 1999 of Light's lead performance in the Broadway play Wit, "It is the sort of transformational work that would hint at other future successes, with Shakespeare, maybe, if a full-time career in the theater were truly an option these days.

[18][19] Light also starred in two television pilots, ABC's sitcom Other People's Kids and USA Network's drama Eden, both in 2011 and neither of which were green-lit to continue.

[23][24] She received positive reviews for her recurring role in Dallas, with Entertainment Weekly naming her the "scene-stealer" of the series.

[25] In 2014, she was cast opposite Jeffrey Tambor in the critically acclaimed Amazon Studios dark comedy-drama series, Transparent created by Jill Soloway.

[29][30] Light appeared opposite Patricia Clarkson in the 2014 rom-com, Last Weekend, and as the mother of Melanie Lynskey's character in a comedy-drama film, We'll Never Have Paris, the same year.

[34] Light received critical acclaim for her portrayal of Marilyn Miglin in 2018's The Assassination of Gianni Versace: American Crime Story, a mini-series on FX, culminating in a Primetime Emmy nomination for Outstanding Supporting Actress in a Limited Series or Movie.

[52] In addition to LGBT and AIDS activism, she has spoken publicly to encourage vaccination against the flu as a way to protect vulnerable populations.