The 1st-3rd Florida spent the winter near Tullahoma, Tennessee, with drilling new arrived recruits and holding target practice. In March 1863 The regiment saw combat around the siege of Vicksburg. Detached to participate in the Jackson Expedition, General Joseph Johnston's relief action, it fought as part of Adams' brigade in the Siege of Jackson. By summer the returned regiment was in the brigade of Marcellus A. Stovall.