Leonard O'Brien

Leonard Francis "Mike" O'Brien (January 20, 1904 – March 30, 1939) was an American field hockey player who competed in the 1932 Summer Olympics and 1936 Summer Olympics.

He was born in North Adams, Massachusetts and died in Boston, Massachusetts.

In 1932 he was a member of the American field hockey team, which won the bronze medal. He played one match as back.

Four years later he was a member of the American field hockey team, which lost all three matches in the preliminary round and did not advance. He played three matches as back.