Callaghan was Liberal candidate for the UnionistEastbourne division of Sussex at the 1918 General Election. His Unionist opponent received endorsement from the Coalition Government and Callaghan finished third. He was Liberal candidate for the Chatham division of Kent at the 1922 General Election. This was another Unionist seat, but this time he finished second as there was no Labour candidate. In 1923 he again contested Chatham, and although a Labour candidate intervened, he again finished second. He did not stand for parliament again.