Born on 29 October 1867, fourth son and seventh child of William Bonamy Maingay, a private gentleman living in Guernsey. He was educated at Clifton College from January 1883 to July 1885, and afterwards entered St Bartholomew's Hospital. In 1894 he was appointed house surgeon at the Scarborough Hospital, and at the end of his term of office entered into partnership with Dr Everley Taylor and Dr F W A Godfrey. He was for many years surgeon to the Scarborough Hospital and was elected consulting surgeon on his retirement in 1919. He was also honorary medical officer to the Filey Road Children's Home. He married Katheleen Edith Lemprière on 3 June 1902, who survived him with two sons, both of whom entered the medical profession. He died on 17 November 1930 and was buried in the cemetery at Scarborough. Maingay was of a retiring disposition; he did his duty well, but took no part in municipal affairs.