[1] Returning to Toronto, he became a newspaper, magazine and book illustrator, appearing in numerous publications, including Hardware Merchandising.

[6] Jefferys created a series of illustrations and essays for the Toronto Star Weekly, which in 1920 were published as Dramatic Episodes in Canada's Story.

[11] Soon after Jefferys's death in 1952, more than 1,000 of his drawings were sold to the Imperial Oil Company, which in 1972 donated the collection to Library and Archives Canada.

[12] A plaque at 4111 Yonge Street, where he died,[13] quotes him as saying, "If my work has stirred any interest in our country and its past, I am more than paid".

[12]Jefferys received numerous awards, including an honorary Doctor of Laws degree from Queen’s University in 1934.