Elected to Congress on the Whig ticket in 1859, Laban T. Moore was an ardent Unionist and a bitter foe of secession, an opinion shared by his law partner and brother-in-law. In October, 1861, following the collapse of Kentucky’s neutrality, Louisa became a rallying point for men of Union sympathies. Moore, Gallup, and other Lawrence County men began organizing the 14th Kentucky Volunteer Infantry. Moore became colonel of the regiment and Gallup became its quartermaster.

When Marshall’s Confederates invaded the Big Sandy Valley in December, 1861, penetrating as far as Paintsville, Moore moved his regiment to Catlettsburg. At that time the citizens of Louisa and Catlettsburg were in a state of panic, fearing that the Confederates would steal their property and burn their houses. At Catlettsburg the 14th Kentucky joined Garfield’s command, and its men were issued rifles, uniforms, knapsacks, tents, and other equipment necessary for a military campaign.

Gallup saw action at Middle Creek, along with three companies of his regiment, but it was not until later in the war that he became the region’s most effective Union commander. In January, 1863, following the resignation of Col. Cochran, Gallup was promoted to Colonel and placed in command of the 14th Kentucky. From August, 1863 to May, 1864, operating from his base at Louisa, Gallup served as Commander of the Military District of Eastern Kentucky.

On February 15th, 1864, at Laurel Creek in Wayne County, West Virginia, Gallup and his regiment, along with men of the 39th Kentucky, surrounded and defeated Col. M. J. Ferguson’s 16th Virginia Cavalry, repaying them for the depredations they had committed at Red House and Turman’s Ferry. On April 14th, 1864, at Puncheon Creek in Magoffin County, Gallup and his regiment, along with the men of the 39th Kentucky, surrounded and defeated Col. Ezekiel F. Clay’s 1st Kentucky Cavalry.