He was first elected to Parliament at the New Westminster riding in a by-election on 24 October 1949, after incumbent Thomas Reid was appointed to the Senate. Mott was defeated in the 1953 election by George Hahn of the Social Credit party.
Mott was also mayor of New Westminster, British Columbia from 1942 to 1948, after serving as alderman there between 1936 and 1940. In 1947 and 1948, he was president of the Union of British Columbia Municipalities.[2] Mott Crescent in the municipality's Victory Heights sector was named in his honour.[3]