Born in Nazareth, Palestine (his father was a missionary), of Scottish ancestory. Received his initial education at Edinburgh University. Emigrated to Canada in 1910. Graduated from Queen's University (B.A. 1926) and University of Toronto (B.Paed. 1928, D.Paed. 1931). Employed as a public school teacher in B.C. (1911-1929), instructor in educational psychology at Vancouver Normal School (1929-1944), and principal and professor of philosophy and psychology at Victoria College (now University of Victoria) (1944-1952). Author of Reflections of a Dominie (1931) and Understanding Yourself and Your Society (1947), coauthor with D.L. McLaurin of Social and Educational Psychology (1937); also wrote many essays and poems.

Ewing was taught chess at an early age, and "was the youngest entrant in the Richardson cup competition playing for Edinburgh. Played in the Edinburgh team for three years without losing a game." He won the B.C. Championship in 1916 and 1919-1923; on entering the 1923 competition Ewing made an announcement "that he would do so for the last time, desiring to make his chess activities for the future a source of real pleasurable pastime rather than a serious and arduous task." In recognition of his sequence of wins the B.C. Championship trophy, the Bowser Shield, was given to Ewing permanently; he responded by donating a new trophy, the Ewing Cup, for the competition. During this time Ewing was also active in team events, playing for North Vancouver, and also played first board for Vancouver in the Vancouver - Winnipeg telegraph match of 1924. In August 1924 Ewing was a participant in the Dominion (Canadian) championship in Hamilton, ON, where he finished with a respectable 8/15. He seems to have retired from competitive play thereafter, but reappeared in the mid-1930s, winning the B.C. championship for a record seventh time in 1936. Ewing also produced and edited a chess magazine (the British Columbia Chess Magazine, subsequently the Canadian Chess Magazine) during the years 1918-1920, but like so many early magazines there simply was not a large enough subscription base for it to survive.