Betterton was elected Member of Parliament for Rushcliffe in Nottingham in 1918. He served under Stanley Baldwin as Parliamentary Secretary to the Ministry of Labour between 1923 and 1924 and again between 1924 and 1929. When the National Government was formed in 1931 he was sworn of the Privy Council and made Minister of Labour under Ramsay MacDonald, a post he held until 1934, when he left from House of Commons after appointment as the chair of the Unemployment Assistance Board.