 He received an honorary degree at Middlebury Collegein Vermont in 1803 and was a trustee from 1811 until his death.He was a member of the Vermont House of Representatives in 1813, 1814, 1817, 1819, 1820, and 1822.Langdon was elected as a Federalist to the Fourteenth Congress, serving from March 4, 1815 until March 3, 1817.