Between 1945 and 1956 R. A. McInnis served as Tasmania’s first Town and Country Planning Commissioner and was charged with the responsibility of winning acceptance for the Town and Country Planning Act 1944, the first major piece of planning legislation in Tasmania. During his period as Commissioner McInnis faced many obstacles and challenges and did not always achieve his objectives, but he was pivotal to the successful implementation of town and country planning in Tasmania. Previous work on McInnis has provided an overview of his work, but this paper will analyse how influential McInnis was in stimulating town planning in Launceston, Tasmania’s second largest city. Town planning enthusiasts in Launceston had been pressing the virtues of town planning since 1915, but without much success because of a lack of effective legislation and of town planning expertise. The context changed with the passage of the 1944 Act and McInnis’ appointment. Although strains and tensions were evident in McInnis’ relations with the Launceston City Council, aldermen and city officials came to rely on his experience and judgement before following through on town planning proposals. On some issues such as extending city boundaries and furthering regional planning McInnis was a valuable ally of the City Council in its relations with the surrounding municipalities that cramped the growth of Launceston. McInnis also assigned his staff, especially Dutch-trained Hans Westerman, to assist with a zoning plan for the city and a regional master plan. McInnis expended considerable energy selling the advantages of town planning to community and business groups and was assisted by visits from English experts such as Patrick Abercrombie and William Holford. The paper concludes that McInnis was an indispensable catalyst for change in Launceston and turned town planning from an unattainable ideal into a practical reality.