At the start of the American Civil War, Vincent joined the Pennsylvania Militia as an adjutant and first lieutenant of the Erie Regiment. On September 14, 1861, he was commissioned lieutenant colonel of the 83rd Pennsylvania Infantry and was promoted to colonel the following June. After the death of his regimental commander in the Seven Days Battles, Vincent assumed command of the regiment. He developed malaria on the Virginia Peninsula and was on medical leave until the Battle of Fredericksburg in December 1862. On May 20, 1863, he assumed command of the 3rd Brigade, 1st Division, V Corps, Army of the Potomac, replacing his brigade commander, who resigned after the Battle of Chancellorsville. near the spot where Vincent was mortally wounded At the Battle of Gettysburg, 26-year-old Vincent and his brigade arrived on July 2, 1863. 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. He had written her, "If I fall, remember you have given your husband to the most righteous cause that ever widowed a woman." Maj. Gen. Daniel E. Sickles of the III Corps had deviated from his orders, moving his corps to a position that left undefended a significant terrain feature: Little Round Top. The chief engineer of the Army of the Potomac, Brig. Gen. Gouverneur K. Warren, recognized the tactical importance of the hill and urgently sought Union troops to occupy it before the Confederates could. A staff officer sent by Warren encountered Vincent's brigade nearby. Vincent, without consulting his superior officers, decided that his brigade was in the ideal position to defend Little Round Top, saying "I will take the responsibility to take my brigade there." Pvt. Oliver Willcox Norton, Vincent's brigade standard bearer and bugler, later wrote that he and Vincent made a reconnaissance of the Confederate forces as the brigade was moving into position, "While our line was forming on the hill at Gettysburg I came out with him in full view of the rebel lines. They opened two batteries on us instantly, firing at the colors. Colonel Vincent looked to see what was drawing the fire and yelled at me, "Down with the flag, Norton! Damn it, go behind the rocks with it.". One of Vincent's regiments, the 20th Maine, led by Colonel Joshua Lawrence Chamberlain, has received most of the fame for the defense of Little Round Top, but there is little doubt that the efforts and bravery of Vincent were instrumental in the eventual Union victory. Vincent impressed upon Chamberlain the importance of his position on the brigade's left flank and then he left to attend to the brigade's right flank. There, the 16th Michigan Infantry was starting to yield to enemy pressure. 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!" A bullet struck him through the thigh and the groin and he fell. Due to the determination of the 20th Maine, the 44th New York, the 140th New York Volunteer Infantry Regiment, the 83rd Pennsylvania and the 16th Michigan Infantry, the Union line held against the Confederate onslaught. 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. The promotion was dated July 3, 1863, but it is doubtful that Vincent knew about the honor before he died Vincent's wife gave birth to a baby girl two months later, who died before reaching the age of one and is buried next to her father. His corps commander, Maj. Gen. George Sykes, described Vincent's actions in his official report from the battle:
Legacy
Vincent is buried in Erie Cemetery in Erie. He is memorialized by a statue on the 83rd Pennsylvania monument on Little Round Top, by a statue erected in 1997 at Blasco Memorial Library, Erie, and by Strong Vincent High School in Erie. The portion of Little Round Top to the southeast of Sykes Avenue on the Gettysburg Battlefield is known as "Vincent's Spur". 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.
