[1] He was the creator and chief editor (1935–1940) of the 4-volume Explanatory Dictionary of the Russian Language with over 90,000 entries.

He was also the creator of an orthographic dictionary of the Russian language (1934).

[1] He influenced his student, Grigoriy Vinokur, who dedicated his book The Russian Language: A Brief History to him.

[2] Ushakov died in Tashkent, where he had been evacuated to during World War II.

[1] His work on a definitive explanatory dictionary of the Russian language was continued by Sergei Ozhegov.