Cotton received the Medal of Honor – the country's highest award for bravery during combat – for his action aboard the USS Baron DeKalb during the Yazoo Pass Expedition between 23 and 27 December 1862.

He enlisted into the United States Navy during the American Civil War.

Cotton was the coxswain aboard the USS Baron DeKalb (initially called the USS St. Louis), and saw action at the battles of Fort Henry and Fort Donelson in February 1862.

Proceeding under orders up the Yazoo River, the Baron De Kalb, with the object of capturing or destroying the enemy's transports, came upon the steamers John Walsh, R. J. Locklan, Golden Age, and the Scotland, sunk on a bar where they were ordered to be burned.

Returning down the Yazoo, she destroyed and captured large quantities of enemy equipment and several prisoners.