- A captain in the 5th Maine regiment (in which his brother Bryce also served).
According to "Edwards Generations" family history,
"Clark Swett Edwards was educated in the public schools of Otisfield, Me. In 1848 he went to Bethel to work. At the opening of the Civil War when the call was made for 300.000 men, he took out recruiting papers and was chosen Capt. of the first company organized under this call in the country. This company became Co. 1, 5th. Me. Regt. He was mustered in as Captain, June 24, 1861, but his rank as such dated from May 4, 1861. He was soon promoted to Major; to Lieut. Col., Sept. 24, 1862; to Col., Jan. 8, 1863; Brevet Gen., Mar. 13, 1865; and was mustered out with rank of Brig. Gen. by brevet for conspicuous bravery, July 27, 1865. He was with the Army of the Potomac in leading engagements. He was Democratic nominee for Governor of Maine, 1886, and appointed by Gov. of Maine in 1890 as Commissioner for Columbian Exposition at Chicago.
He is included on the Civil War page.
His papers are kept at Navarro College's Civil War collection (at http://www.nav.cc.tx.us/library/civilwar/finding_aids/a_f/edwards.htm). The page also gives a full history of his service during the war.
You can order a photo of him from here, at the Maine State Archives: