Patterson left Disney in 1941 during an animation strike. He would briefly reunite with Screen Gems before moving to the Metro-Goldwyn-Mayer cartoon studio, with his first short for them being "War Dogs". While he mostly worked in the studio's Hanna-Barbera unit, he occasionally provided animation for Tex Avery's unit in the 1950s (as well as Avery's substitute director Dick Lundy). He worked on several Academy Award-winning animation shorts: "Mouse Trouble" (1944), "Quiet Please!" (1945), "The Little Orphan" (1948), and "Johann Mouse" (1952). Patterson (along with his college Irven Spence) would briefly leave MGM in the mid 40's. During this period, he would help organize and educate animators from David Hand's Gaumount British Animation Studio. He and Spence would later move back to MGM in the late 40's.