[1] From August to September, 1861, he helped raise a company of men for military service, and reported to Benton Barracks at St. Louis, Missouri, for induction.

On February 4, 1862, with the rest of the regiment, Campbell embarked by steamboat, and was transported by river, finally disembarking at Fort Henry, Tennessee.

In early October, a combined Confederate Army under Maj. Gen. Earl Van Dorn and Maj. Gen. Sterling Price attempted to recapture the city.

The Western Sharpshooter fought a bitter skirmish, on October 4, 1862, the second day of Second Battle of Corinth against elements of the Confederate Missouri Brigade in the timber in front of the Federal lines.

Col. Thomas W. Sweeny commander of the 52nd Illinois Infantry who observed the fight, declared that the Sharpshooters "fought like heroes".