His grandfather was a cantonist who had been drafted from Libava (today Liepāja), Latvia, and who settled in Siberia after 25 years in the Imperial Russian Navy.

After graduating from the institute in 1931, Mil began his career at TsAGI, too late to work under its original founder, Nikolay Zhukovsky.

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.

In 1971, after his death, his Mil Mi-12 (production name of V-12 prototype) won the Sikorsky Prize as the most powerful helicopter in the world.