Bendiner graduated from the City College of New York in 1933. He received an honorary degree of Doctor of Humane Letters from the Long Island University in 1994.
Bendiner began his career as a managing editor of the the Nation magazine in 1937 and held it for seven years. Then in 1946, he became an associate editor of the same magazine, where he worked until 1950. Robert was a freelance writer of The Nation in 1951-1968 and again from 1978 until his death in 2009.
Also in 1946, he took a position of chairman at Wellesley Summer Institute Social Progress, where he served until 1953. Robert was a member of the faculty at the Salzburg Seminary in American Studies in 1956 and a visiting lecturer in journalism at Wesleyan University in 1983.
Bendiner was a member of the National Press Club and club, Coffee House in New York City. He was a member of the editorial board of the New York Times.
On December 24, 1934 Robert Bendiner married Kathryn Rosenberg. The marriage produced 3 children.