In 1880, he set up practice in Toronto and also lectured on eye, ear and throat diseases at Trinity Medical School.

Ryerson helped found the Association of Medical Officers of the Canadian Militia and served as president from 1908 to 1909.

Ryerson helped establish the St John Ambulance Association in Ontario and the Canadian Red Cross Society.

Sir William Mulock, PC, KCMG, KC, MP, afterwards Post-Master-General and Chief Justice of Ontario.

Mary Crowther Ryerson and daughter Laura were passengers aboard the Lusitania when it was sunk off the Irish coast in May 1915.