With the outbreak of the Civil War, young Chew raised a battery of horse artillery, "Chew's Battery," which eventually became part of the famous Laurel Brigade under Stonewall Jackson's command. He and his brother John A. Chew participated in all Jackson's campaigns until Jackson's death in May 1863. Chew also led raids into Union-occupied Middleway, West Virginia in February 1863, and Charles Town on May 12, 1863. Despite his youth, Roger Chew was promoted to the chief of the cavalry's guns under J.E.B. Stuart. He then served through the Gettysburg Campaign, the Wilderness, Spotsylvania Court House, Cold Harbor, the Siege of Petersburg, and the Appomattox Campaign.