Plunkett studied law at the University of California when he became interested in theater. He first played as an actor on stage and students also began to design the sets and costumes. Finally, he went to New York City, but could, except for some gigs in Greenwich Village, not profile as an actor. In 1925 he came to back to California and tried to be an actor in Hollywood. However, his talent for designing costumes was larger and in 1927 he designed his first costumes for a Hollywood film. As early as the 1930s, when Chefkostümbildner at RKO, he was one of the most important Hollywood costume designers. Despite many successes, the films for which he designed the costumes, he received during his career only one Oscar: 1952 for An American in Paris, which he had to share with Orry- Kelly and Irene Sharaff. Plunkett had designed the only ball costumes.