Marshall was born in Minneapolis, Minnesota, on January 13, 1924, as Marriam Patricia Murphy.

In the same year, Marshall had a role as a nurse playing poker in an episode of M*A*S*H, which her husband created.

She was married to Gelbart until he died in 2009 from cancer, leaving behind a son and daughter from his marriage to Patricia Marshall.

[1][3] In 1946, Marshall won a Theatre World Award for her role in the Broadway play The Day Before Spring.

[6] Marshall died at the age of 94 on December 11, 2018, at her residence in Westwood, Los Angeles in the presence of her family.