Loxton entered the Victorian parliament in 1955, and served as government whip from 1961 until his retirement in 1979. At the time of his election, he was the youngest member of parliament, and was given the honour of making the Address-in-Reply, the first speech after opening of the new sitting by the governor, using it to advocate increased lending from the government-owned banks to promote higher levels of home ownership. At the 1958 election, Loxton consolidated his hold on the seat, leading on first preferences (43.67%), and ending with 54.85% of the two party preferred vote to halt Pettiona's attempted comeback. During the election campaign in 1961, a campaign meeting in Prahran that was attended by Premier Bolte and Loxton drew several hundred people and descended into chaos; heckling and some scuffles broke out. At this election, the Liberals' primary vote fell to 41.69% behind the Labor Party's candidate George Gahan 45.29%, and he had to rely on DLP preferences to retain the seat with a reduced two party preferred vote of 52.71%. The Liberals may have been hindered by a how-to-vote card circulated on election day by a third party that had a pro-Liberal headline, but instructed the reader to mark the ALP candidate as their first preference. Loxton managed to secure a court injunction—believed to be the first of its kind in Victoria—prohibiting further distribution of the material, but not before hundreds of misleading instructions had been disseminated.