Reynolds first served under Brigadier General John B. Floyd in western Virginia. In March 1862, Reynolds was sent to the Western Theater. He joined Edmund Kirby Smith's command in the Army of Kentucky throughout the rest of 1861 and most of 1862. After the Kentucky Campaign failed in its object, Smith's army joined General Braxton Bragg's Army of Tennessee in a reorganization of Confederate forces in the Western Theater. On December 16, 1862, Confederate President Jefferson Davis ordered the transfer of Major General Carter L. Stevenson's division to Lieutenant General John C. Pemberton's army. Reynolds utilized the political connections of his brother-in-law, Virginia Delegate Mason Mathews, to lobby for his promotion to general officer with Secretary of War James Seddon. General Reynolds, commanding a brigade in Stevenson's division, went with his troops to Vicksburg.