After graduating from the institute in 1931, Mil began his career at TsAGI, too late to work under its original founder, Nikolay Yegorovich Zhukovsky. He specialised in the design of autogyros, and was an assistant to his future rival, Nikolay Kamov. With the start of World War II, Mil was drafted into the Red Army and fought on the Eastern Front in 1941 near Yelnya. In 1943 he was called back to continue research and development in improving the stability and control of combat aircraft. He completed his dissertations ("Candidate", 1943, PhD, 1945) and in 1947 headed the Helicopter Lab at TsAGI, which was later turned into the Moscow Helicopter Plant.