When William Alexander Thistlethwaite was born on 21 December 1878, in Asphodel, Peterborough, Ontario, Canada, his father, William Thistlethwaite, was 35 and his mother, Jane McGee, was 29. He married Elizabeth McDonald on 19 February 1908, in Saskatoon, Saskatchewan, Canada. They were the parents of at least 2 daughters. He lived in Saskatoon, Saskatchewan, Canada in 1911. He died on 19 July 1953, in British Columbia, Canada, at the age of 74.