John Newman was the son of Austrian and Yugoslav parents, who settled in Cabramatta when he was a small child. He was educated at Cabramatta Primary School and Liverpool High School. He went on to work at Borg Warner in Fairfield. In March 1972 he changed his surname by deed poll to Newman. He had a long history of involvement with the labour movement and with the Australian Labor Party, spending much of his working life as a union official. He was a State union organiser with the Federated Clerks Union from 1970 to 1986. Newman completed post-graduate studies in industrial law at the University of Sydney, and undertook a variety of Trade Union Training Authority education programs.
Newman was elected an alderman on Fairfield Council in 1977 and remained on the council for 10 years. He was Deputy Mayor in 1985-86 and also served as Acting Mayor in 1986. In December 1979 Newman's pregnant wife, Mary, and five-year-old son, David, were killed in a automobile accident at Bossley Park.
Following a by-election in the seat of Cabramatta, Newman was elected to Legislative Assembly of New South Wales on February 1, 1986. Since the 1970s, Cabramatta has been a centre for immigrants and refugees from Asian backgrounds, particularly Vietnam, China, Laos, Cambodia, Thailand and Korea. For many years Newman had been waging a campaign to break up the Asian crime gangs and corruption that had plagued the area.
He had been the target of numerous death threats from such gangs but did not seek police protection. During the night of September 5, 1994 while outside his home, he was shot and killed. His fiancee, Lucy Wong, was with him at the time but saw little of what happened because of its swiftness and suddenness.
A local nightclub owner, Phuong Ngo, who had previously attempted to secure Labor Party pre-selection for the seat, was convicted of the killing in 2001. Two of Ngo's associates escaped convictions. In 2003, an appeal by Ngo against the conviction failed.
Newman's death has made him something of a martyr. This helped the Labour Party to win back the seat in the Cabramatta by-election that followed in a landslide. A local swimming pool has been named after him.