MB ChM Sydney 1918; FRCS Edin 1923.
Mercer was house surgeon at MRI and Manchester Ear Hospital before being appointed visiting aural surgeon to Hope Hospital Salford. He was later consultant surgeon for ENT at Eccles and Patricroft Hospital and surgeon in charge of the ENT department at Salford Royal Hospital. Mercer was also honorary surgeon to Manchester Ear Hospital and visiting aural surgeon to Park Hospital, Davyhulme. Mercer was a fellow of the Royal Society of Medicine. He died on 23 January 1975, aged 80.