According to his attestation papers dated August 5, 1915 at Toronto, Leonard Alfred Blake was born on January 11, 1896 at Newfort GBW (?), England. He listed his father Herbert Blake, Melrose Street, Mimico as his next of kin. He was a journalist and had no previous military experience. He was 19 years and 7 months of age and stood 5 feet 8 inches tall. He had blue eyes, dark brown hair and a dark complexion. He was a member of the church of England.
His brother Charles also enlisted but was killed. According to Charles obituary Leonard was with the Records Department in London.