A five-time Tony Award nominee, she won the Tony Award for Best Featured Actress in a Play for A Delicate Balance in 1967, and received subsequent nominations for Father's Day (1971), Deathtrap (1978–82), Ring Round the Moon (1999), and Dinner at Eight (2002).

She was inducted into the American Theater Hall of Fame in 1995 and received the Special Tony Award for Lifetime Achievement in 2010.

Seldes's paternal grandparents were Russian-Jewish immigrants, and her mother was from a "prominent WASP family," the "Episcopalian blue-blooded Halls.

She went on to an illustrious career in which she earned five Tony Award nominations, winning her first time out in 1967 for A Delicate Balance.

In addition to performing in live theatre, Seldes began acting in television in 1952 in a Hallmark Hall of Fame production that marked the first of many guest star roles.

Half Hour to Kill was a proposed but unrealized television series mystery show with episodes hosted by Vincent Price and planned to occasionally star him as well.

(1958)[citation needed] Seldes appeared in every one of the 1,809 Broadway performances of Ira Levin's play Deathtrap, a feat that earned her a mention in the Guinness Book of World Records as "most durable actress".

"[11] In 2012, Seldes played the knife-wielding socialite Mabel Billingsly in the film adaptation of Wendy Mass' popular children's book Jeremy Fink and the Meaning of Life, written and directed by Tamar Halpern.

"Rick" Rodgers, chronicling Seldes' last years, had created "consternation in the theater world" as a "horrific, intrusive depiction of her slide into dementia".