According to his attestation papers dated January 17, 1916 at Mimico, Joseph Brennan of Mimico, Ontario was born on March 1, 1885 in Lancashire, England. He listed his wife, Mrs. Nellie Brennan, Mimico, as his next of kin. He was a labourer and an active member of the 12th Regiment, York Rangers. He was 30 years and 10 months of age and stood 5 feet 9 1/2 inches tall. He had blue eyes, fair hair and complexion. He was Roman Catholic.
In the 1921 Toronto City directory he is listed as a car repairer living on the west side of Station Road, Mimico.