Roos was placed 25th on the DA's Gauteng regional list and 83rd on the party's national list for the
8 May 2019 National Assembly election. At the election, he won a seat in the National Assembly. Roos was sworn in as a
Member of Parliament on 22 May, two weeks after the election. On 27 June 2019, he became an alternate member of the
Portfolio Committee on Home Affairs. He became a full member of the committee on 7 February 2020 and was appointed Shadow Deputy Minister of Home Affairs. Roos criticised the electoral amendment bill that would allow for individuals to stand for election to parliament and provincial legislatures as
independent candidates after it was passed by the National Assembly in October 2022, arguing that the bill discriminates against independent candidates because it consigns them to contesting only the regional lists by treating provinces as constituencies, but bars them from standing as candidates on the national proportional representation list. Having been re-elected to the National Assembly in the
2024 general election, Roos was elected to serve on the Magistrates Commission. ==References==