After the war, Lewis returned to Glasgow and resumed the practice of law. He was again elected to the Kentucky House in 1868 and chaired that body's Committee on Education. In 1870, he was elected to the U.S. House of Representatives to fill the vacancy caused by the resignation of Jacob S. Golladay. At the next general election, he was elected to a full term. He was not a candidate for renomination in 1872. In all, he served from May 10, 1870, to March 3, 1873.