According to his attestation papers, dated November 8, 1915, James Watt was born in Cruden, Aberdeenshire, Scotland on January 18, 1879. He listed his wife May Watt, Mimico as his next of kin. He indicated that he was a labourer and that he had no previous military experience. He was 38 years, 10 months old and was 5 feet, 4 1/2 inches tall with blue eyes and brown hair with a fresh complexion. He had a 4 inch scar on the right side of his back. He was a Presbyterian.
According to the 1912 Toronto City directory he was a bricklayer living on the north side of Portland Street, Mimico.