A pupil of the National Academy of Design in New York City, USA, he trained in Paris with the famous French portraitist Emile Auguste Carolus-Duran (1838–1917).

The Canadian Irwins were Late Loyalists, i.e. those loyal to the British Crown who emigrated to Canada after the American Revolution had ended.

He returned to the United States in 1879, where he spent time in Boston and New Bedford, Massachusetts; Louisville, Kentucky, New York City, and Yonkers, throughout the 1880s and 1890s.

Postmortem revealed that Irwin had drowned after being knocked unconscious by hitting his head on the edge of the boat as he fell.

The Catalogue of The Southern Exposition in Louisville, published in 1884, while Irwin was still alive, correctly lists his years of study under Carolus-Duran as 1877–1878.