Colley was first elected to Dáil Éireann on his second attempt at the 1944 general election. He remained a Teachta Dála (TD) until he lost his seat at the 1957 general election to the future Taoiseach, Charles Haughey. He was elected to Seanad Éireann by the Labour Panel in 1957. He did not contest the 1961 Seanad election.
His son, George Colley, was elected to the Dáil at the 1961 general election. George Colley went on to hold a number of Cabinet positions including those of Minister for Finance and Tánaiste. He was defeated in the 1979 Fianna Fáil leadership election by the man who unseated his father – Charles Haughey.