It was proclaimed in 1900 and was one of the original 75 divisions contested at the first federal election. Second only to the nearby Division of Wentworth, the Division of North Sydney has the nation's second highest proportion of high income families. As with all North Shore seats, the division has usually been a comfortably safe seat for the Liberal Party of Australia and its predecessors. Labor has usually run dead in this seat, though it came within 3.1 percent of winning it at the 1943 election landslide. North Sydney and Wentworth are the only two federation divisions in New South Wales to have never been held by Labor. It has been held by a member of a non-Labor party for all but six years of its existence, when held by "father of the independents" Ted Mack, from the 1990 election before choosing to resign from federal parliament after two terms at the 1996 election, for the same reason he previously chose to resign from state parliament after two terms − to avoid receiving a parliamentary pension. However, during Mack's tenure, North Sydney was always a safe Liberal seat in traditional two-party matchups, and it was a foregone conclusion that it would revert to the Liberals once Mack retired. As expected, when Mack retired in 1996, Joe Hockey reclaimed the seat for the Liberals on a swinglarge enough to revert the seat to its traditional status as a comfortably safe Liberal seat. Hockey held it easily until 2015, serving as Treasurer from 2013 to 2015 in the Abbott Government. After Abbott was ousted as Liberal leader and Prime Minister by Malcolm Turnbull in the September 2015 Liberal leadership spill Hockey moved to the backbench, however six days later he announced his intention to resign from parliament, taking effect from 23 October. The 2015 North Sydney by-election occurred on 5 December to elect his replacement, Trent Zimmerman, a former Hockey staffer, despite a large swing. Zimmerman won with 48.2 percent of the primary vote after a larger-than-predicted 12.8 percent swing against the Turnbull Coalition Government. This was only the second time in North Sydney since federation that the successful Liberal candidate did not obtain a majority of the primary vote and had to rely on preferences. Zimmerman faced a double-digit primary vote swing − more than triple that of the 2015 Canning by-election − even though Labor did not even contest the seat. The Liberaltwo-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 percent cannot be 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 became the first openly LGBTI member of the House of Representatives. Besides Mack and Hockey, other notable members from this seat include Dugald Thomson, a minister in the Reid Government, and Billy Hughes, who served as Prime Minister, was the longest-serving parliamentarian in Australian history, and a minister in the Lyons, Page, Menzies and Fadden governments.
