When he first entered the War, Clingman was the commander of the 25th North Carolina Infantry and took part in the Peninsula Campaign. He later commanded a brigade of infantry. Clingman's Brigade consisted of the 8th, 31st, 51st and 61st North Carolina Infantry. Clingman's Brigade fought at Goldsboro, Battery Wagner, Drewry's Bluff, Cold Harbor, Petersburg, Globe Tavern, Fort Fisher, and Bentonville.