Hentoff began his career in broadcast journalism while hosting a weekly jazz program on Boston radio station WMEX. In the 1940s, he hosted two radio shows on WMEX: "JazzAlbum" and "From Bach to Bartók". In the early 1950s he continued to present a jazz program on WMEX, and as a Staff Announcer for WMEX, he regularly hosted remote broadcasts from the "Savoy", and "Storyville", two Boston clubs run by George Wein, and during that period was an announcer on the program "Evolution of Jazz" on WGBH-FM. In 2013, the "Evolution of Jazz" series was contributed to the American Archive of Public Broadcasting by the University of Maryland's National Public Broadcasting Archives as part of the National Association of Educational Broadcasters (NAEB) collection.