[2] Manings was born in Newark, New Jersey to a Jewish family, and was raised on Staten Island.

He served in the United States Army during World War II in the Pacific theater.

Manings felt uneasy during the McCarthyist period, during which time several friends were blacklisted, and moved to Canada until the early 1960s.

Manings was elected vice president of the Writers Guild of America, West from 1975 to 1977 and also served as a member of its board of directors from 1977 to 1982 and again from 1985 to 1992.

He died on May 12, 2010, aged 86, in Beverly Hills, California of a heart attack in addition to esophageal cancer from which he was suffering and had been receiving medical treatment.