According to his attestation papers dated April 12, 1915 at Toronto, William Craib was born on December 8, 1896 in Aberdeen, Scotland. He listed his mother Martha Craib, 173 Fern Avenue, Toronto as his next of kin. He was a plumber, unmarried and had no previous military experience. He was 19 years and 4 months of age and stood 5 feet 5 inches in height. He had blue eyes, brown hair and a fair complexion. He was a Presbyterian.
His brother Alexander also enlisted.