Joseph S.G. Sweatt was born in Boscawen, New Hampshire, on October 23, 1843. During the American Civil War, he moved to Lowell, Massachusetts, where he entered military service. He served as a Private in Company C of the 6th Massachusetts Infantry.

On May 15, 1863, Sweatt’s unit was engaged in combat at Carrsville, Virginia. During the battle, his company was ordered to retreat. Instead of withdrawing with the main body of troops, Sweatt turned and ran back toward the front lines under heavy enemy fire.

His objective was to rescue wounded comrades who had been left behind during the movement. Sweatt reached the fallen soldiers and remained by their side to provide aid and protection. He continued this effort until he was eventually overpowered by Confederate forces and taken as a prisoner of death. For these actions, he was later recognized for his bravery under fire.