While Senator Joseph McCarthy grabbed headlines with his shouts of "Communist", Hoover set about his self-appointed task of purging Hollywood of any he viewed as "disloyal" to the United States, which meant anyone unwilling to make the movies they were told to make, when and how they were told to make them. Senator McCarthy's screed of "Communist" provided Hoover with a bludgeon he could and did use with impunity on Hollywood's creative talents. Careers were ruined. Some 400 people, mostly innocent of any actual wrongdoing, were destroyed. Some, like Jean Seberg would later do, committed suicide. Ten men (the famous Hollywood Ten), Alvah Bessie, Herbert Biberman, Lester Cole, Ring Lardner jr., John Howard Lawson, Albert Maltz, Samuel Ornitz, Adrian Scott, Dalton Trumbo, and eminent director Edward Dmytryk were jailed for contempt of Congress.

Others punished for refusing to cooperate included Larry Adler, Stella Adler, Leonard Bernstein, Marc Blitzstein, Joseph Bromberg, Charlie Chaplin, Aaron Copland, Hanns Eisler, Carl Foreman, John Garfield, Howard Da Silva, Dashiell Hammett, E. Y. Harburg, Lillian Hellman, Burl Ives, Arthur Miller, Dorothy Parker, Philip Loeb, Joseph Losey, Anne Revere, Pete Seeger, Gale Sondergaard, Louis Untermeyer, Josh White, Clifford Odets, Michael Wilson, Paul Jarrico, Jeff Corey, John Randolph, Canada Lee, Orson Welles, Paul Green, Sidney Kingsley, Paul Robeson, Richard Wright and Abraham Polonsky. Lee Grant was registered on the black list because she refused to give evidence against her husband Arnold Manoff.

Stars such as Larry Parks were destroyed because they refused to "name names" of other actors who were party members. Actor Philip Loeb threw himself out of a skyscraper window. Edward G. Robinson, never a communist, was put on a "grey list," and spent the rest of his life making B movies (except for his final role opposite Charlton Heston in "Soylent Green"). Sam Jaffe, formerly a well-known actor and Oscar winner in 1950 was registered on the black list because he refused to cooperate with the committee. He spent the next 6 years working as a math teacher and living at his sister's until he was able to return to films in 1957.