Service in the Australian Military Forces from 1942 to 1946, as a corporal in the 21st Field Ambulance turned Bill Berns' ambitions from being a music teacher to a medical career. He obtained his musical diplomas while at Sydney High School. He left school early and matriculated after he was discharged, then studied medicine at Sydney University. Graduation in 1953, was followed by intern training at Sydney Hospital, then at Crown Street Women's Hospital, following which he was appointed to Sydney Hospital as medical registrar in 1955.
He entered general practice in partnership where he remained for five years, and it was during this time that he gained his MRACP in 1958. After this time, he entered full-time practice as a general physician practising in Bondi Junction and Macquarie Street, his major hospital being Eastern Suburbs Hospital, to which he was appointed honorary assistant physician in 1967. His privileges extended to Prince Henry and Prince of Wales Hospitals in 1972, the same year he was elected FRACP. Two years later, he was appointed to Crown Street Women's Hospital.
Marriage in 1953, his wife and three children, his musical interests as a pianist and lawn bowling were his major outside interests. Orthodoxy led him to Israel in 1976, but this proved frustrating and disappointing, and he returned to his medical life in Sydney after a brief stay. His relatively sudden death from myocardial infarction followed his male family pattern, and he died in St Vincent's Hospital on 14 February 1987.