May was elected as a Democrat to the 56th United States Congress, and served from March 4, 1899, to March 3, 1901. From 1906 to 1910, he was a member of the New York City Board of Education. He was an Assistant District Attorney of Kings County from 1910 to 1911.
He was Secretary of State of New York from 1913 to 1914, elected in 1912, but defeated for re-election in 1914. He was county judge of Kings County from 1916 to 1921, and was a justice of the New York State Supreme Court from 1922 to 1940, when he retired after reaching the constitutional age limit. Afterwards he resumed the practice of law.
According to a biographer of Governor Al Smith, May played a role in desegregating a New York country club. As told by Hugh Carey, Smith and May were about to tee off when club officials attempted to stop them because of May's religion—the club did not admit Jewish members. Smith replied that either May would play the round with him, or Smith would have the golf course turned into a state park within a week. They played, and the club changed its membership policy.
- Slayton, Robert A. (2001). Empire Statesman: The Rise and Redemption of Al Smith. Simon and Schuster. p. 176.
- McBride, Joseph (1992). Frank Capra: The Catastrophe of Success. University of Mississippi Press. p. 244.
- Mitchell May at Find a Grave
- Stone, Kurt F. "The Jews of Capitol Hill: A Compendium of Jewish Congressional Members, (2011). Pages 71–73. ISBN 9780810857315.
- United States Congress. "Mitchell May (id: M000276)". Biographical Directory of the United States Congress.
- Mitchell May at Jewish Telegraphic Agency
|United States House of Representatives|
James R. Howe
|Member of the U.S. House of Representatives
from New York's 6th congressional district
George H. Lindsay
|Secretary of State of New York