He was selected to stand in Aberdeenshire North and Moray East in the 2024 United Kingdom general election, and was defeated by the SNP's Seamus Logan.

Following the resignation of Jackson Carlaw in July 2020, Ross announced his candidature in the August 2020 Scottish Conservative Party leadership election.

[7] Ross stood as the Conservative candidate for Moray at the 2010 and 2015 general elections, coming second to Angus Robertson but increased his share of the vote by 5.0% in 2015.

[14][15] SNP and Labour spokespeople criticised Ross for missing a debate on Universal Credit in October 2017, due to his commitments as a football referee.

[17] Despite backing remaining in the EU prior to the referendum, Ross stated Parliament should complete Brexit to "deliver the will of the British people".

[19] He resigned from this role on 26 May 2020, in protest against Dominic Cummings continuing to serve as Chief Adviser to the Prime Minister after having travelled over 260 miles (420 kilometres) from London to Durham during the COVID-19 lockdown period.

[20][21] Ross announced his candidature in the August 2020 Scottish Conservative Party leadership election following Jackson Carlaw's resignation on 30 July 2020.

[23] As a result of the Alex Salmond parliamentary inquiry in early 2021, Ross called on opposition parties to pass a motion of no confidence against the Scottish Government.

[35] Less than two months later, in response to the invasion of Ukraine, Ross announced that he had withdrawn his letter, saying “the middle of an international crisis is not the time to be discussing resignations”.

[47] Following his election as leader of the Scottish Conservative Party, Ross stated that he wanted to represent "working-class unionists in Scotland.

"[48] However, he has also criticised what he views as too much centralisation around London and has expressed support for some federalist ideas, including House of Lords reform.

[50] Ross backed Remain during the EU referendum, but after the vote he stated Parliament should complete Brexit to "deliver the will of the British people".

During the 2019 Conservative Party leadership election, Ross initially endorsed Mark Harper before backing Boris Johnson in the final round.

[53] He continued his refereeing career after being elected to the Scottish Parliament[54] and also officiated matches whilst an MP in the UK House of Commons.

[55] In the House of Commons Register of Members' Interests, Ross declared earnings of more than £2,700 in August and September 2017 for his work as an assistant referee.

[15][56] In October of that year, Ross told the football authorities that he would no longer accept refereeing appointments during the week while the UK Parliament is sitting.

[57] In December 2018, BBC Sport reported that Ross had reduced the number of refereeing appointments due to his work commitments as an MP.

[58] In August 2020, Ross apologised for not attending a VJ Day event as a result of previously agreeing to officiate at a Scottish Premiership game between Kilmarnock and St Johnstone.

[60] In November 2020, FIFA were asked to investigate a complaint by a member of the Scottish Football Supporters Association that a Conservative Party leaflet distributed to homes in Scotland included a photograph of Ross as a match official.