In April 1913, Fadden moved to Mackay to become assistant town clerk of the Mackay Town Council. He defeated 56 other applicants for the position. In 1916, his superior, Frederick Morley, was dismissed as town clerk over allegations of theft, which Fadden himself had uncovered. Morley eventually received a two-year jail term, and Fadden was promoted in his place, again defeating more than 50 other applicants; he was reputedly the "youngest town clerk in Australia". He had attempted to enlist in the Australian Army the previous year, but was rejected on health grounds. In 1918, Fadden served on the committee of the relief fund for the Mackay cyclone, which devastated the town and killed thirty people. However, he resigned as town clerk in September of that year and moved to Townsville (the largest settlement in North Queensland), where he established his own accountancy firm. He had qualified as an accountant through a correspondence course from a school in Melbourne.