Cato was the son of F J Cato a business man in Melbourne. After attending Wesley College, Cato commenced his medical studies at the University of Melbourne; while a student he received a severe back injury, which always gave him trouble, but did not restrain his enormous vitality. He qualified in 1917, and immediately volunteered as a medical officer in the first Australian Imperial Force, and was later awarded the Military Cross for bravery in the field. On returning to Australia he served his residency at the Alfred Hospital and then went to England to obtain the Fellowship. While in England Cato worked for a time at the West Middlesex Hospital, returning to Australia in 1926 to take up the appointment of out-patient surgeon to the Alfred Hospital, Melbourne, and later he was appointed surgeon and then consulting surgeon to the Austin Hospital there. During the second world war Cato served in the RAF with the rank of Wing Commander and was stationed in England. His chief surgical interests were in bone and spinal diseases, and he conducted a busy private practice. Outside medicine his interests were many and varied, including golf, fishing, shooting and flying at which he obtained a pilot's licence. Later in life he took up painting and several exhibitions of his work were held in Melbourne. His first marriage was to Marjorie Gibbs, but both she and their two sons died, one of them in a bombing raid over Germany. Late in life he married Marjorie Vasey, who survived him. He died in Melbourne after a long illness on 8 February 1966.