Lacking combat experience, J. Johnston Pettigrew was loath to accept a brigadier generalship and actually sent the commission back to the Confederate War Department. The North Carolinian had taught at the Washington Naval Observatory and studied law in the United States and Germany. Practicing in Charleston, he was involved in the militia and became an officer.

His military assignments included: colonel, 1st South Carolina Rifles (November 1860); private, Hampton (S.C.) Legion (1861); colonel, 12th North Carolina Volunteers July 11, 1861); colonel, 22nd North Carolina (designation change on November 14, 186 1); brigadier general, CSA (February 26, 1862); commanding French's (old) Brigade, Aquia District, Department of Northern Virginia(March 12-mid April 1862); commanding brigade, Whiting's-G.W. Smith's Division, same department (April-May 31, 1862); commanding Martin's (old) Brigade, Department of North Carolina (September 1862 February and April 1-May, 1863); commanding brigade, Hill's Command, Department of Virginia and North Carolina (February-April 1, 1863); commanding brigade, Heth's Division, 3rd Corps, Army of Northern Virginia (May 30-July 1 and July-July 14, 1863); and commanding the division July 1-mid July 1863).

After commanding his rifles at Fort Sumter, he went to Virginia as a private but was appointed to the colonelcy of the North Carolina regiment before 1st Bull Run. He served that winter in the Fredericksburg area and the next spring moved to the Peninsula. After the Yorktown siege he was wounded and captured at Seven Pines. Exchanged in late August 1862, he commanded a brigade in southern Virginia and North Carolina until May 1863 when it was ordered to Lee's army. At Gettysburg he succeeded the wounded Herb in charge of the division and led it in Pickett's Charge two days later. During the retreat he was mortally wounded on July 14 at Falling Waters while commanding his brigade. Carried back to Virginia, he died three days later.