John T. Carthew was born in Suffolk, England on February 15, 1891.
He was registered as an Alberta Land Surveyor on April 17, 1913. He joined the war effort on September 1, 1914 in London as a private with the Coldstream Guard.
He saw quite a bit of action and was wounded twice (Loos in 1915 and Somme in 1916). His brother, William Morden Carthew, also an Alberta Land Surveyor, was killed in action.