In 1877, Goodnight was elected to the
Kentucky House of Representatives, serving a single, two-year term. He served as the chairman of the
Democratic Kentucky convention at
Louisville, Kentucky in 1891. He was elected to represent the
Third District in the
U.S. House of Representatives in 1888. He was twice re-elected, serving in the Fifty-first, Fifty-second, and Fifty-third Congresses (March 4, 1889 – March 3, 1895). During his tenure, he was a member of the
Judiciary Committee, rising to third in seniority on that committee by the end of his third term. ==Later life and death==