Zimmerman was born in Sydney and is one of two children of Roy and Brenda Zimmerman. His father, Roy Zimmerman, was Master-in-Charge of the GPSpreparatory schoolWyvern House from 1966 until 1996. Zimmerman attended Newington College, commencing in Wyvern House in 1974 and completing his HSC in 1986.
Politics
After working in the Parliament of New South Wales, Zimmerman became a ministerial adviser in the federal government of John Howard in the environment and heritage portfolio and later as an adviser to then Shadow Treasurer Joe Hockey. He was President of the Young Liberal Movement of NSW from 1992 to 1993. Zimmerman was a councillor on North Sydney Council for two terms until the local government elections of 2012. During his time as a councillor, Zimmerman lived openly as a gay man and worked actively on LGBTI issues, describing the de-funding of the NorthAIDS program as "unforgivable". He also served as Vice President of the Sydney Gay and LesbianBusiness Association. In the September 2008 Council Elections, Zimmerman ran for the position of Mayor of North Sydney, against the log-serving incumbent since 1995, Genia McCaffery. He was unsuccessful, taking only 40% of the vote, and later commented that "I worked very hard at it and I have no qualms at the issues I raised". During his time at Council, Zimmerman advocated on environmental issues around developments, including leading opposition to a controversial development in Vale Street, Cammeray. In 2012, Zimmerman was anointed as the Liberal left's candidate for the seat held by Jillian Skinner; but Skinner decided to stay on in parliament, deferring Zimmerman's political ambitions.
Federal parliament
Zimmerman won the 2015 North Sydney by-election with a 48.2 percent primary vote after a larger-than-predicted 12.8-point swing against the Liberals − more than triple that of the 2015 Canning by-election. It was only the second time since Federation that the Liberals did not obtain a majority of the primary vote. Remarkably, this came in the absence of a Labor candidate; Labor has only come close to winning this normally safely conservative seat once, in 1943. The Liberal two-candidate vote of 60.2 percent against independent Stephen Ruff compares to the previous election vote of 65.9 percent against Labor. The reduction of 5.7 points is not generally considered a "two-party/candidate preferred swing" − when a major party is absent, preference flows to both major parties does not take place, resulting in asymmetric preference flows. Zimmerman was preselected as the Liberal by-election candidate which was triggered by the resignation of former treasurer Joe Hockey. Zimmerman's appointment was controversial, with now-suspended party member Juris Laucis describing the process as "undemocratic" and "a stitch-up" and reform activist and former Liberal party member John Ruddick called for Liberal voters feeling disenfranchised to send a message to the party by giving Zimmerman their last preference. Political journalist Peter Hartcher attributed his preselection to his being an ally of Michael Photios, "the power behind the NSW machine". Whilst a candidate for preselection, Zimmerman was also the head of the body that sets the rules for party elections, a position his opponents described as a "complete conflict of interest." Ted Mack, Hockey's predecessor in the seat, ran a campaign against Zimmerman on behalf of Stephen Ruff, the independent who ran second in the by-election. Zimmerman is one of eight openly LGBTI current members of the Parliament of Australia and the first openly LGBTI member of the House of Representatives. Zimmerman has indicated he will speak out on LGBTI issues and declared his support for Gay marriage in Australia and stated "I would have supported a free vote and preferred it to be decided by the Parliament. But that's the path we are going to go down so I will be strongly advocating, both in North Sydney and more broadly, a Yes vote for that plebiscite". Zimmerman was sworn into parliament on 2 February 2016.
