The Fourteenth Infantry Regiment was organized at Fond du Lac, WI, and mustered into the service of the United States on January 30, 1862. It left the state on March 8 and reported to General Grant at Savannah, TN, March 28, 1862 where it encamped. On the 6th it moved to Pittsburg Landing. On the 7th of April the Fourteenth was engaged in the conflict there, now generally known as the Battle of Shiloh. After the battle, the Fourteenth remained at Pittsburg Landing as provost guard, participating in numerous expeditions against the enemy, and in the battle of Corinth October 3-4, 1862.

In November 1862 the Fourteenth joined the forces concentrating at Grand Junction, TN for an advance on Vicksburg. After the Confederates' destruction of the army stores collected at Holly Springs, the Fourteenth, with other forces, participated in several expeditions in S.W. TN, moving to Memphis January 13, 1863. On the 17th it embarked down the River to join the force operating against Vicksburg. On the 13th of May it crossed the river below Vicksburg and participated in the movements of the Union forces. On the 19th the 14th took position in the trenches in the rear of Vicksburg and continued to take part in the siege of that place until July 4, when the Confederates surrendered. On the 14th of July it accompanied Ransom's Brigade, participated in the capture of Natchez, MS and remained there until October, when the regiment returned to Vicksburg.

In March 1864, the Fourteenth joined the forces assigned to the Red River Expedition, March 10-May 22, 1864, and participated in numerous minor engagements in which that command was engaged. In July following was a part of the forces accompanying the expedition to Tupelo, MS, July 5-21, 1864, and participated in the engagements July 13, 14 and 15th. After the return from that district it was assigned to active service in northern Arkansas. In November 1864 the regiment was transferred to Nashville, TN, which was reached November 30, and took part in the battle of Nashville, December 15-16, 1864.

After that battle the Fourteenth was engaged in the pursuit of the Confederates until the latter part of January, 1865, when the Regiment was transferred to New Orleans and assigned to a position in the Sixteenth Army Corps. With this force it took part in the Mobile Campaign, March 17-May 4, 1865, and the investment and capture of Spanish Fort March 27-April 8, 1865. Co. E. and members of other companies became detached from the regiment in March 1864 and attached to Leggett's division of the 17 Army Corps, and with this organization participated in the Atlanta, Savannah and Carolinas campaigns and the Grand Review in Washington, D.C., May 24, 1865, rejoining the regiment in Alabama, July 16, 1865. Thereafter the Fourteenth performed guard duty in Alabama until October 1865. It was mustered out and reached Madison, WI, October 22, 1865 where it was discharged from the military service.