Everybody says that the term “disc jockey” was coined in the 1940s, but nobody wants to own up to coining the term. The guilty party turns out to be Walter Winchell, a writer for the New York Daily Mirror and radio host. Winchell's column appeared in almost 2,000 newspapers And on the air he dished gossip at a purported average of 197 words per minute.
He started out writing jokes free-lance for Billboard. He must have been funny because he ended up as a columnist for the The Vaudeville News. By the 1920s he was a professional Journalist writing a gossip column 'Your Broadway and Mine'' dedicated to harassing vaudeville entertainers. He himself had been a vaudeville entertainer with the Gus Edwards Newsboys Sextet as was his wife. Apparently he left the stage somewhat bitter. I'm not sure where in there he Americanized his real name from Walter Weinschel.
Walt made his radio debut in 1930 on WCBS-AM. His big move came two years later on the NBC’s Blue Network when he was shuffled onto The Jergens Journal, a popular news program. That program mixed in entertainment news with hard news giving him the opening to start talking trash. While his column was at the peak of it's popularity in 1937. (some sources cite 1934) He was used it to refer to fellow radioman Martin Block as a "Disc Jockey". Block spun records on the program "the Make Believe Ballroom" on WNEW. Block played up the the illusion that the program was broadcast from a ballroom. Martin Block went on to become a wildly popular DJ. The Make-Believe Ballroom idea was actually stolen from another DJ named Al Jarvis.
By the 1960s Winchell's career was in the tank. He's mistakenly supported McCarthy and it stained him for life. His radio show was canceled, and the daily Mirror went under. Ed Sullivan and Jack Paar were openly mocking him and his son committed suicide. He died a recluse of cancer in 1972. Id' also like to note that he exchanged correspondence for decades with America's most famous republican cross-dresser, J. Edgar Hoover. More here. Winchell was inducted into the radio hall of fame in November, 2004.