Railway Mail Service
Hart was elected as a Republican to the 39th United States Congress, holding office from March 4, 1865, to March 4, 1867. He was an unsuccessful candidate for reelection in 1866 to the 40th United States Congress and was superintendent of the Railway Mail Service for the States of New York and Pennsylvania from 1869 to 1876. In 1883 he died in Rochester; interment was in Mount Hope Cemetery.