Born in Kensington, London, Leonard Moon was the younger brother of Corinthians and England goalkeeper Billy Moon, who also played cricket for Middlesex. He attended Westminster School and Pembroke College, Cambridge, where he obtained his blue for Cambridge and played for The Corinthians as a forward for several seasons. He went on The Corinthians’ tours to Hungary and Scandinavia in 1904 and scored 8 goals in an 11-0 win in a match against Stockholm on the latter tour, scoring 5 in another match against the same opponents.
As a cricketer he scored 7 first-class hundreds while playing for Cambridge University from 1897 to 1900 and Middlesex from 1899 to 1909. He played four Tests for England against South Africa in 1905-06, averaging 20.75 with the bat.
In the First World War he joined the 10th Battalion, Devonshire Regiment, attaining the rank of Second Lieutenant. Moon died of his wounds on 23rd November 1916 near Karasouli, Salonica, Greece aged 38.