At the start of the American Civil War, Vincent joined the Pennsylvania Militia as an adjutant and first lieutenant of the Erie Regiment.

He had started the Gettysburg Campaign knowing that his young wife, Elizabeth H. Carter, whom he had married on the day he enlisted in the army, was pregnant with their first child.

Mounting a large boulder, Vincent brandished a riding crop given to him by his wife and shouted to his men "Don't give an inch!"

Vincent was carried from the hill to a nearby farm, where he lay dying for the next five days, unable to be transported home due to the severity of his injury.

The commander of the Army of the Potomac, Maj. Gen. George G. Meade, recommended Vincent for promotion to brigadier general on the evening of July 2.

His corps commander, Maj. Gen. George Sykes, described Vincent's actions in his official report from the battle: Night closed the fight.

Vincent, Weed, and Hazlett, chiefs lamented throughout the corps and army, sealed with their lives the spot intrusted to their keeping, and on which so much depended.

The 1-112 Infantry of the Pennsylvania Army National Guard stationed in Cambridge Springs uses the call sign "STRONG" in recognition of Vincent's courage, determination and sacrifice.