Born in 1871 in Delaware County, Ohio, Willis attended a small country school before finally graduating from Ohio Northern University in Ada, Ohio in 1893. In 1899 he was elected to the State Legislature. He failed to gain the Republican nomination for a run for Congress in 1904. Willis went back to school, and was admitted to the Bar Association in 1906. He retained his connection with teaching and thus served on the staff of Ohio Northern University from time to time for many years, primarily in the School of Law. Willis finally won election to Congress, and re-elected to a second term in 1912. In the 1914 election he won the Ohio Governorship. He lost his bid for reelection in the 1916 campaign, losing to former Governor Cox, and he proceeded to lose again in 1918. His political career rebounded when a Senate seat opened when Warren F. Hardings vacated it for his run for the Presidency. Willis won that U.S. Senate seat.