The Fifth Minnesota Volunteer Infantry Regiment's Civil War service included participation in thirteen campaigns, five sieges and thirty-four battles, including duty on Minnesota's frontier during the US–Dakota War of 1862. They were the last of the state's regiments to form in response to President Lincoln's first call for troops.
Mustering into service at Fort Snelling in spring 1862, seven of the ten companies departed for the South in May. They were assigned to General John Pope's Army of the Mississippi in front of the town of Corinth. Just four days after arriving, the men of the Fifth received their baptism of fire at the Battle of Farmington. The men behaved well in the battle, which was a Union victory and resulted in the eventual capture of Corinth. The Confederates were forced to abandon western Tennessee and northern Alabama and Mississippi.
In the months following the battle, the Fifth spent much of the summer guarding railroads in Mississippi and Alabama. The hard marching and excessive southern heat took its toll on the officers and men and many of them fell ill. It was around this time that the Fifth's colonel, Rudolph von Borgersrode, resigned. Lieutenant-Colonel Lucius F. Hubbard, a future governor of Minnesota, was promoted to command of the regiment.
Meanwhile, Companies B, C, and D had been kept in Minnesota and sent to various posts nearby. Company B was stationed at Fort Ridgley. On August 18 a forty-six-man detachment under Captain John S. Marsh departed the fort for the Lower Sioux Agency in response to the conflict there. They were ambushed at Redwood Ferry on the Minnesota River. This was the first encounter between the Dakota and US troops since the US Dakota War began. Captain Marsh drowned in the confusion of the retreat, and his detachment suffered twenty-three killed and five wounded. Those remaining made it back to Fort Ridgley and were soon joined by fifty men from Company C. This combined force, along with fifty Renville Rangers and a few cannon, defeated the Dakota attacks against the fort on August 20 and 22. On September 3 and 6, Company D successfully defended Fort Abercrombie, Dakota Territory, from additional Dakota assaults.
Back in Mississippi, the rest of the Fifth fought in the Union victories of Iuka on September 19 and Corinth on October 3-4. At Corinth, a gap opened in the federal lines. The Confederates began pouring through the gap and captured some cannon. The Fifth Minnesota rushed in and attacked these troops in the flank, closing the gap and recapturing the cannon. The Minnesotans were instrumental in turning the tide of battle.
In December 1862, Companies B and C rejoined the regiment, followed by Company D in February 1863. On May 14, 1863, during the Vicksburg Campaign, the Fifth fought the Battle of Jackson, a relatively easy Union victory. On May 22, however, the tables turned as the federal troops were soundly defeated in their attack on the Confederate works at Vicksburg. Due to the nature of the ground, the brigade to which the Fifth belonged charged by the flank rather than in line of battle. This put the Fifth in the rear of the attacking column, sparing the regiment the high casualties of the leading units.
The Fifth Minnesota was present when Vicksburg surrendered on July 4, 1863. The following February many men of the Fifth re-enlisted, earning the title of "Veteran Volunteers." For the next three months the Fifth took part in the failed Red River Campaign in Louisiana. By this time, Colonel Hubbard had been promoted to brigade command.
On December 15–16, 1864 the regiment fought in the Battle of Nashville. On the second day of the battle the men advanced across an open field towards the Confederate forces. They suffered a withering fire, and 106 men were killed or wounded. The battle, however, was a resounding Union success. During the battle, the Fifth's Lieutenant Thomas P. Gere captured the flag of the Fourth Mississippi Regiment.
In early 1865 the Fifth participated in the campaign against Mobile, Alabama. They were mustered out of service at Demopolis on September 6 and then returned to Minnesota, arriving back at Fort Snelling on September 22.