Rex Rienits worked on various Australian newspapers until 1949, when he moved to London. He then became a full-time freelance writer, writing radio and television plays for the BBC and film scripts for various production companies. He wrote his first radio play when he was 22 years old, in 1931. He co-wrote (with second wife Thea Rienits) Early Artists of Australia (1963), The Voyages of Captain Cook (1968), Discovery of Australia (1969), A Pictorial History of Australia (1969) and The Voyages of Columbus (1970). He was editor-in-chief of Australia's Heritage : The Making of a Nation, a series of weekly educational magazines (1970-1976).
Reinits first wife, Josephine (Balfe) Reinets, was the daughter of Oscar Balfe, editor of the Tasmanian Courier (an illustrated weekly published by The Examiner): her brothers Harold Balfe and Eric Balfe were also both journalists. According to her obituary, she was 'a talented pianiste and elocutionist and was highly appreciated in Australian musical circles, taking part in repertory theatre work while in Sydney' (Cairns Post, 29 January 1954, p.5). She died in London on 25 January 1954.