In 1932 Joyce entered commercial radio, working in various stations across Australia, and eventually rising to station manager. He could not enlist during World War II because of a childhood injury, so instead he served as an air-raid warden. At this time he wrote a regular and occasionally controversial column in Radio Times under the pseudonym 'Slapper'.
He formed Donovan Joyce Productions in 1945. For his new company he wrote and commissioned dramas and documentaries for radio, many of which he exported, particularly to South Africa, where he also advised on local radio production. Although Joyce wrote the script for a television episode of 'Homicide' in 1966, he never adapted to writing for the small screen.
Joyce travelled to Israel in 1964 to investigate a scroll allegedly written by Jesus Christ, but he claimed that he was prevented by Yigael Yadin from visiting the archaeological digs at Masada, where he claimed that the scroll had been discovered. After a brief return to radio in Australia, he published The Jesus Scroll (Sydney, 1972; London, 1973), a ground-breaking story of the life of Christ which became a best-seller and led to death threats and continuing controversy.
Joyce died of hypertensive heart disease on 16 October 1980, aged 69, at Prahran and was cremated. He is survived by his wife and a son.