 He also served as supervisor of Plymouth Township in 1842, 1843, 1844, and 1850.In 1850, Penniman defeated incumbent Democrat Alexander W. Buel to be elected as a Whig from Michigan's 1st congressional district to the Thirty-second Congress, serving from March 4, 1851 to March 3, 1853.He was the first Plymouth citizen elected to the United States Congress.