Post-1953, his scripts are credited as by "Joel Carpenter". Manoff"s first screenplay was made into the 1944 film Manitoba from Frisco. Three more of his screenplays were made into movies prior to his being blacklisted: My Buddy (1944), Casbah (1948, starring Peter Lorre and Yvonne De Carlo), and Number Minor Vices (1948, starring Dana Andrews, Lilli Palmer, and Louis Jordan).
Manoff moved to New York City in 1950.
By 1953 his promising Hollywood career was ruined. Thereafter, he was only able to write for television under the pseudonym of "Joel Carpenter." Most notably, he wrote episodes for the Naked City (1962-1963), Route 66 (1963-1964), and The Defenders (1965) series.
On February 10, 1965, Manoff died of a heart attack in New York City at the age of 50.