Edgerton was a delegate to the convention that formed the Free Soil Party, in 1848. He then served as prosecuting attorney of Summit County, Ohio, from 1852 to 1856. Later in 1856, Edgerton was a delegate to the first Republican National Convention. That same year, he was nominated for probate judge, but he declined the nomination. Edgerton was elected as a Republican to the United States House of Representatives in 1858.