He worked odd jobs in New York City and absorbed the intellectual atmosphere of Greenwich Village, an enclave of avant-garde culture where small presses, art galleries, and experimental theater thrived.

He was a member of the Group Theater in the 1930s and appeared in Johnny Johnson, Night Music, Boy Meets Girl, The Time of Your Life (as Willie the pinball machine addict) and other Broadway plays.

During World War II, he served in Army Special Services in Australia and Manila and was cited twice for directing and staging shows for troops overseas, as well as teaching acting classes.

Lee also began appearing in movies, including bit parts in Casbah, A Song Is Born, Little Fugitive, and Saboteur.

He was blacklisted as an alleged communist and barred from movies and TV for five years during the era of McCarthyism, according to members of his family.

He taught at the American Theatre Wing for nine years (including among his students James Earl Jones), as well as at the New School for Social Research, Boston University, and the Uta Hagen-Herbert Berghof Studio.

The New York Times reported that on Sesame Street, Lee's Mr. Hooper ranked ahead of all live cast members in recognition by young audiences, according to a survey.

Following Lee's death, the producers of Sesame Street faced the challenge of how to address the absence of one of the series' most prominent characters.

Caroll Spinney (Big Bird and Oscar the Grouch) said that the last time he saw Lee alive was during the taping of the last episode involving Mr. Hooper in November 1982.

Lee died on December 7, 1982, at the age of 74, from a heart attack at Lenox Hill Hospital in New York City.