 He graduated MB BS at the University of London in 1887 and joined Leeds General Infirmary as house surgeon.He was then successively demonstrator of anatomy in the Medical School (1893–96), assistant surgeon to the infirmary (1896), surgeon from 1906 and consulting surgeon from 1927 until his death.In parallel with his appointment as surgeon, Moynihan was lecturer in surgery from 1896–1909, and from 1910–1927 Professor of Clinical Surgery (from 1925 Surgery) at the University of Leeds.