Morrison held the post of Speaker until 1959, when he announced that he would not be contesting the forthcoming general election but retiring for reasons of health. As was customary for former Speakers, he was made a Viscount, taking the title Viscount Dunrossil, of Vallaquie in the Isle of North Uist and County of Inverness. Given his health, it surprised many when it was announced shortly thereafter that he had been chosen to succeed Sir William Slim as Governor-General of Australia. He was also appointed a Knight Grand Cross of the Order of St Michael and St George (GCMG) that year. By this time support for the idea of British governors-general was declining in Australia, but the Liberal Prime Minister, Robert Menzies, was determined to maintain the British link (and, in particular, the Scottish link).