John Roland Grimoldby was born in Sheffield on 2 April 1912, the son of Edward John Grimoldby, a gentleman's outfitter, and Edith (née Woodcock). He was educated at Barnsley and District Holgate Grammar School and the University of Sheffield. He graduated BSc with first class honours in 1933 before starting clinical work at the medical school qualifying in 1936. After early hospital appointments he passed the FRCS in 1947 and four years later emigrated to New Zealand, accepting the appointment of surgeon to Taumaranui Hospital. In 1959 he was appointed the first superintendent-in-chief to the Hawke's Bay Hospital Board where in addition to his professional duties he played an important role in planning many of the new hospital buildings, including the operating theatre block. His other interests were the Medical Research Society of New Zealand of which he was a founder member and the St John Ambulance Association which he joined in 1951. After retiring from hospital work he devoted his life to his hobbies of stamp collecting and gardening. He married Alice Margaret Edgeley (known as Peggy), a nursing sister, in 1945 and they had one daughter, Judith. He died on 23 May 1989 at the age of 77.