General Robert E. Lee was preparing his troop concentration at Mechanicsville. Generals D.H. Hill and James Longstreet were positioned on the Mechanicsville Turnpike and General A.P. Hill's Division was in place near Meadow Bridge Road. Branch's Brigade, which included the 7th Regiment, was positioned to the right of A.P. Hill's left. General T. J. Jackson forces were moving to the left of Branch's Brigade. The attack plan called for A.P. Hill to move on Mechanicsville on the morning of June 26, 1862. Branch and Jackson's troops were to immediately move to the left of Hill. Once Hill had cleared the Mechanicsville Turnpike of Federal forces, D.H. Hill was to cross to support the Confederate left. Colonel Haywood proceeded from the Brook turnpike up the Telegraph Road to the Chickahominy River. There they stayed until the next day waiting for orders. There was some confusion as to where General Jackson was. At 3:30 a.m., the Brigade moved out with the 7th Regiment leading. When they crossed the Chickahominy River, they were thrown into action along with Companies A and C. Their purpose was to dislodge the Union pickets between them and the Meadow Bridge. They met 200 Union forces and they attacked and drove them from their position. The Union flag was captured along with several of the company books and memoranda. The 7th Regiment suffered some wounded but none killed in this action. The next engagement with the Federals was at Atlee Station on the Virginia Central Railroad. The Regiment had a severe skirmish and suffered heavy casualties. From there, the unit headed for Mechanicsville and arrive just before dark under intense fire from the Union forces. After some reorganization under General Archer, the unit bivouacked for the night. The Federal forces had retired to a defensive position at Gaines Mill. By 3:00 a.m., the 7th Regiment was ordered ready to move to the front and shortly was met with fire from Union sharpshooters and Union batteries.

   On the morning of June 27, 1862, the Confederates moved against the Gaines Mill Union position.  A.P. Hill and James Longstreet moved directly in front of the enemy position while Jackson and D. H. Hill moved to strike the right flank.  A.P. Hill's forces were in the advance attack and made the first enemy contact.  As the battle ensued, Longstreet sent his men in on Hills right and Jackson and D.H. Hill came in on the left side. Meanwhile, the 7th Regiment had been ordered to take a position on the road.  It was discovered that the Union forces had abandoned that position so the unit marched to Gaines Mill. They arrived between 3 and 4 p.m. that day and were immediately ordered into action. Two companies were thrown into service as skirmishers as they advanced up the right hand road. Upon being engaged by the vastly superior enemy, the entire Regiment immediately supported the other two companies. Colonel Campbell realized that he was not going to be reinforced as quickly as he thought so he gave up the position he had been defending for some time. He ordered his regiment into the woods where the companies became separated. Lt Col Haywood found himself with only three companies, Companies A, B, F and a portion of Company G. These troops were rallied and reported to Major General Hill for orders. All companies eventually were united.

Major General Ewell ordered the 7th Regiment to change its position from the woods to cross a swamp and felled trees, then up a hill to where the Union forces were entrenched. Colonel Campbell was mortally wounded in the charge. Corporal Henry T. Fight of Company F was carrying the colors when he was shot down. Then Corporal James Harris of Company I grabbed the colors and he, too, was shot. Then Colonel Campbell took the colors and as he advanced 20 paces in front of his men, he was also shot and died. Lt. Duncan Haywood, commanding Company E. seized the flag and he too was killed. The flag of the 7th Regiment was then carried from the field by Corporal L.B. Peavy of Company C. The flag staff had been shot into. By that time, it was nightfall Nearly half of the 7th Regiment had been destroyed. The flag had literally been shot to pieces and had 32 mini-ball holes in it. The flag attested to the heavy fire that the 7th Regiment endured in this battle.