John Hughes studied medicine at Cambridge and St Bartholomew's Hospital. After early appointments as house surgeon at the Miller General Hospital and Hampstead General Hospital he became assistant medical officer to Down's Hospital, Sutton. He became a Fellow of the College in 1936 and moved to Sheffield in 1938, practising at Montague Hospital, Mexborough. Sometime in the 1940s or early 1950s, he moved to the USA taking an appointment at the Central State Hospital, Lakeland, Kentucky. He then moved to Poquoson, Virginia and on to Hampton, Virginia, where he is thought to have died, possibly in 1989.