He was member of the Maryland State Senate, representing the western shore, from 1826 to 1830.

[1][2] He was elected as a Jacksonian to the Twenty-second Congress to fill the vacancy caused by the death of George E. Mitchell and served from October 1, 1832, to March 3, 1833.

He was again elected as a Democrat to the Twenty-seventh Congress to fill the vacancy which was caused by the death of James W. Williams, and served from January 2 to March 3, 1843.

They had six children: Charles S. Jr., Edwin Augustus, Jacob Keazy, Septimus Davidge, James Monroe and Ann Maria.

[2] Sewall died at Rose Hill in Harford County on November 3, 1848.