When Grey was first created in 1903, it included the Northern Territory and all of northern and western South Australia, down to a line through the Mid North south of Port Pirie. Grey has been held by Labor for most of its history, and was one of the few country seats where Labor usually did well. It remained in Labor hands for all but one term from 1943 to 1993, the only break coming when the Liberals won it during their landslide victory in 1966. For most of that time, it was a fairly safe Labor seat, though it was almost lost in the Coalition landslides in 1975 and 1977. That changed in 1993, when the retirement of Labor incumbent Lloyd O'Neil, the unpopularity of the state Labor government, and the addition of the Clare Valley at a redistribution, which saw Liberal Barry Wakelin become the fifth non-Labor member to win the seat, and only the second in 50 years. That happened even as Labor won another term; it was the first time Labor had won government at an election without winning Grey. However, as mentioned, the election came at a bad time for the state Labor government, which was roundly defeated at the state election later that year. Wakelin was re-elected with a large swing in 1996, and since then the decline in the mining and pastoral vote has made it a fairly safe Liberal seat. While the "Iron Triangle" towns of Whyalla, Port Augusta and Port Pirie still tilt Labor — as they have for more than a century — that is not enough to overcome the increasingly conservative lean in the rest of the seat. The Liberals consolidated their hold on the seat ahead of the 2004 election when the Yorke Peninsula and the state's upper east, both historically strongly conservative areas, were transferred to Grey from Wakefield. The Liberals suffered a nine-point swing at the 2007 election, but Rowan Ramsey was still able to retain the seat for the Liberals, with 54 percent of the two-party vote. The seat became secure for the Liberals once again after Ramsey picked up a large swing in 2010, which he consolidated in 2013.
South Australian Senator Nick Xenophon confirmed in December 2014 that by mid-2015 the Nick Xenophon Team would announce candidates in all states and territories at the 2016 election, with Xenophon citing the government's ambiguity on the Collins-class submarine replacement project as motivation. ABCpsephologist Antony Green's 2016 federal election guide for South Australia stated NXT had a "strong chance of winning lower house seats and three or four Senate seats". Going into the 2016 election, Grey was the second-safest Liberal seat in South Australia; Labor needed a 13-point swing to win it. A ReachTEL seat-level opinion poll in Grey of 665 voters conducted by robocall on 9 June during the election campaign surprisingly found NXT candidate Andrea Broadfoot leading the Liberals' Ramsey 54–46 on the two-candidate preferred vote. Seat-level opinion polls in the other two rural Liberal South Australian seats revealed NXT also leading in both Mayo and Barker. Early counting following the poll showed that Broadfoot was a clear second to Ramsey on first preferences, well ahead of the ALP candidate in third place. This meant that the indicative assessment of two-candidate preferred count on election night had been done between the wrong pair, and would need to be redone in the following week to give a clearer indication as to which of Ramsay and Broadfoot would win the seat after distributing all preferences. While Broadfoot was ahead with as much as 80 percent of ballots counted, she ultimately lost to Ramsey on Family First preferences. Ultimately, Ramsey suffered a swing of 11.6 percent after preferences were counted, which made Grey the most marginal Liberal seat in the state and one of the most marginal Coalition-held rural seats in the nation. On a "traditional" two-party basis, however, Grey was still a fairly safe Liberal seat.
