Peter Reay Bull was born in Adelaide on 18 December 1919. His father was Lionel Batley Bull, a veterinary pathologist, and his mother Beatrice Johanna Reay, whose father had been a journalist. He was educated at St Peter's College, Adelaide, and qualified MB BS from the University of Melbourne in 1943.
He became a JRMO at the Alfred Hospital from 1943 to 1945 and worked at the Austin Hospital from 1946 to 1951. In 1951 he became tuberculosis officer at the Department of Health and remained in that post until 1960 when he became deputy director of tuberculosis in the Department of Health. In 1964 he was appointed honorary chest physician of the Austin Hospital.
He wrote several papers on the surgery and chemotherapy of tuberculosis in the Medical Journal of Australia. Peter married Thelma Ruby McIllree. There were no children of the marriage. His hobbies included music, woodwork and gardening. He died on 31 August 1990.