Born in Garrycloyne Castle, near Cork (Republic of Ireland), the eldest son of the Reverend John Lewis and Rebecca Olivia Lawless, Lewis studied at Trinity College, Dublin. He was made a Deacon in 1848 and a priest in 1849. He served as priest at Newtownbutler in County Fermanagh, before emigrating to Canada in 1849 to be with his mother who emigrated the year earlier. He was posted to Hawkesbury and later in 1854 to Brockville. In 1861, he was appointed the first Bishop of Ontario (Kingston). In 1893, he became metropolitan of the ecclesiastical province of Canada and then Archbishop of Ontario. He resigned in 1900.
John Travers Lewis married Annie Henrietta Marguerite, daughter of Henry Sherwood, at one time Attorney-General for Upper Canada. Their son, Travers Lewis, was a barrister in Ottawa. Their eldest daughter, Charlotte Sherwood Lewis, was born at Brockville, Ontario, and educated at Toronto, Ontario. She married Robert Craigie Hamilton, son of Col. George Hamilton of Hawkesbury, Ont., at Ottawa, Ontario on April 28, 1875. Their eldest daughter (born in Montreal) married Wilfrid Sergeant. Their son served as a midshipman and Captain's A.D.C. on H.M.S. Irresistible.