Moulton was an attorney for the Rutland Railroad from 1902 to 1903, and then worked as an associate at the Townsend & Avery firm in New York City. In 1910, Moulton was one of the founding partners of Cowles, Moulton, & Stearns, a law firm located in
Burlington, Vermont. He left the firm in 1912, and established a Burlington office in which he was the principal. Moulton was active in politics as a
Republican; he was a member of the Burlington Republican Committee from 1910 to 1912, and was chairman beginning in 1911. From 1911 to 1913, and again from 1915 to 1916, he served as Burlington's grand juror, responsible for pursuing prosecutions in the city court. ==Continued career==