After her work with George Stevens, Perkins was placed under contract to 20th Century Fox. She was one of the promising young stars of Hollywood, but the studio contract system, which was coming to an end, was a poor fit for Perkins, who had come of age with the Beat Generation in 1950s New York City. George Stevens would later state: "Millie did not fit in. She was 10 years too early." Suspended for refusing the lead in the 1960 film Tess of the Storm Country – Perkins saw the film as a B-picture and a step back career-wise – Perkins was cast by 20th Century Fox in the 1961 film Wild in the Country, playing the supporting role of the girlfriend to star Elvis Presley – she would later play Gladys Presley in the 1990 miniseries Elvis; the studio then dropped Perkins. Joshua Logan personally selected Perkins for the female lead in the 1964 film Ensign Pulver but the film was a failure: Perkins would not appear in another mainstream film release for almost twenty years. She played the female lead in both of Jack Nicholson's inaugural productions The Shooting and Ride in the Whirlwind – shot side by side in 1965 – and in 1968 co-starred in Wild in the Streets which was written by her then-husband Robert Thom.