His legislative service coincided with the end of World War I and the Red Summer of 1919, which witnessed the rise of the second Ku Klux Klan.

With the Klan's endorsement he was elected to the United States House of Representatives in 1924, defeating Democratic incumbent William E. Wilson in Indiana's 1st congressional district.

Klan-backed candidates won up and down the ballot in 1924, with local Klan leader D. C. Stephenson widely believed to have orchestrated the nomination of the incoming Republican governor, Edward L. Jackson.

He was defeated for re-election to the 72nd Congress in 1930 following the onset of the Great Depression, which was blamed on the Republican Party and the administration of Herbert Hoover.

During his final term in office, Rowbottom was indicted for accepting bribes in exchange for appointments to jobs with the United States Postal Service.