He was unsuccessful National Liberal candidate for Motherwell at the 1922 General election. He sat as a Member of Parliament for Midlothian and Peebles Northern from 1929 to 1943 and served in the National Government as Parliamentary Secretary to the Department of Overseas Trade from 1931 to 1935, as Under-Secretary of State for Scotland from 1935 to 1936, as Financial Secretary to the Treasury from 1936 to 1938 and as Secretary of State for Scotland from 1938 until 1940. Colville left Parliament in 1943 to become Governor of Bombay, a post he held until 1947. He acted as Viceroy and Governor-General of India, in 1945, 1946 and 1947. On his return from India he was raised to the peerage as Baron Clydesmuir, of Braidwood in the County of Lanarkshire. From 1950 to 1954 Lord Clydesmuir served as a Governor of the BBC.