James Kevin McGuinness (December 20, 1894 – December 4, 1950) was an American screenwriter and film producer. He provided testimony to the House Un-American Activities Committee which led to the Hollywood blacklist in 1947.
McGuinness was born on December 20, 1894, in Drogheda, County Louth, Ireland, and immigrated to New York in 1904.
McGuinness was one of the earliest editors and contributors at The New Yorker magazine; in the March 14, 1925, issue, he profiled the boxer Jack Dempsey and continued to contribute pieces (nonfiction, fiction, and poetry) until 1927. He relocated to Los Angeles in the late 1920s, at the dawn of the "talkies" era, and thereafter worked in the film industry as a writer and producer. He wrote for 36 films between 1927 and 1950. He eventually became chief supervisor and executive producer at Metro-Goldwyn-Mayer.
In 1947, along with fellow screenwriter Jack Moffitt, he testified against others suspected of Communist leanings in Hollywood for hearings associated with the House Un-American Activities Committee, which led to the Hollywood blacklist.
McGuiness died in New York on December 4, 1950, from a heart ailment.