Austin settled in St. Albans, became active in politics as a Republican, and served in several local offices, including Grand Juror, Chairman of the city Republican committee, and State's Attorney of Franklin County (1904-1906). In 1908, he was chairman of the state Republican convention, and he served as Mayor of St. Albans from 1909 to 1910. From 1907 to 1915, Austin was a Commissioner for the United States Court of Appeals for the Second Circuit. In 1917, he moved to Burlington, where he continued to practice law. Austin's prominence continued to grow, and he served as a University of Vermont trustee from 1914 to 1941, and an attorney practicing before the United States Court for China from 1916 to 1917. Austin served as a special counsel for the state of Vermont from 1925 to 1937 during the process of setting the official boundary between Vermont and New Hampshire.