He was elected as Member of Parliament for North West Hampshire at the 2015 general election. Following the 2018 cabinet reshuffle, Malthouse was appointed Parliamentary Under-Secretary of State at the Department for Work and Pensions. After Dominic Raab was appointed Brexit Secretary, Malthouse served as Minister of State for Housing and Planning from 2018 to 2019. Malthouse was credited as the convener of an agreement between limited factions of the Conservative Party on Brexit, "The Malthouse Compromise" in January 2019. The compromise was later voted down in Parliament in March 2019.