 He was appointed postmaster of Addison on June 15, 1878, and served until July 26, 1886.Gillet was elected as a Republican to the Fifty-third and to the five succeeding Congresses (March 4, 1893 – March 3, 1905).He served as chairman of the Committee on Expenditures in the Department of Agriculture (Fifty-fourth through Fifty-seventh Congresses), Committee on Public Buildings and Grounds (Fifty-eighth Congress).