At the 2017 general election, Walker stood in the electorate of. The Clutha-Southland electorate has been held since its creation in 1996 by the National Party. Walker was selected as a last minute candidate to replace Todd Barclay, who had resigned due to an employment scandal. Walker won Clutha-Southland, defeating Labour candidate Cherie Joy Chapman by a margin of 14,354 votes. During his first term, Walker lobbied for the preservation of maternity services in Lumsden and greater support for Queenstown businesses affected by the COVID-19 pandemic in New Zealand. Walker was also a member of Parliament's primary productionselect committee and served as the party's associate agriculture spokesperson between 12 March 2018 and 25 May 2020. Between 25 May and 7 July 2020, Walker served as National's spokesperson on forestry and land information, and associate spokesperson on tourism. On 2 July 2020, Walker attracted media attention when he issued a press release criticising the Labour-led coalition government for not consulting residents of Dunedin, Queenstown, and Invercargill about hosting quarantine facilities for 11,000 returnees from India, Pakistan and South Korea. Walker's remarks were criticised as racist by Minister of HousingMegan Woods for singling out returnees from those countries. Walker defended his remarks, asserting that charges of racism were an attempt to deflect from the Government's failings. Prime MinisterJacinda Ardern criticised Walker's remarks as inappropriate while Mayor of DunedinAaron Hawkins described Walker's remarks as "dog whistling." On 3 July 2020, Walker was reprimanded by National Party leader Todd Muller, who expressed disappointment and concern about his press statement. According to Stuff, Walker's statements had not been approved by the National Party's leadership. On 7 July 2020 Walker admitted leaking sensitive medical information to media outlets about COVID-19 patients and was stripped of his portfolios. That same day, former National Party president Michelle Boag admitted passing COVID-19 patient details to Walker and resigned from her position as chief executive of the Auckland Rescue Helicopter Trust. On 8 July, National leader Todd Muller told the media that he had written to the party board asking them to remove Walker from the party. That same day Walker announced that he would not be standing for re-election in the Southland electorate during the 2020 New Zealand general election.
