When the state expanded its small artillery battalion into a regiment in November 1776, Harrison was appointed commander with the rank of colonel.

[2] On 1 December 1775, the Virginia Convention authorized a state artillery company, including a captain, three lieutenants, one sergeant, four corporals, four bombardiers, eight gunners, and 48 matrosses.

A committee appointed James Innis captain while Harrison, Edward Carrington, and Samuel Denney became lieutenants on 13 February 1776.

[4] On 26 November 1776, Congress authorized Harrison's Continental Artillery Regiment to be made up of 10 companies, including the two existing units.

[7] After British commander Sir Henry Clinton threw back Charles Lee's 5,000-man advance guard, he was finally stopped in front of Washington's main line of battle.

[8] Clinton tried to break Lord Stirling's left flank, but the effort failed in the face of heavy musketry and effective fire delivered by a battalion of artillery under the tactical direction of Carrington.

[4] Carrington took three batteries of the 1st Regiment south with Johann de Kalb in 1780, but Harrison arrived "unexpectedly" to claim seniority.

[13] Otho Holland Williams recalled that Harrison's guns were massed in the center near the main north-south road.

One of Harrison's officers, Captain Anthony Singleton pointed out to Williams that the British troops were about 200 yards (183 m) away and received permission to open fire.

During the pre-battle maneuvers, Greene sent the guns 20 miles (32 km) back to the Lynches River to avoid capture.

[15] As Rawdon's attack approached, Harrison's masked battery cut loose with case shot, halting the British.

Subsequent children were Charles II (d. 23 November 1796), Mary Herbert (11 September 1766 – 15 January 1833), Benjamin Henry (1770 – 1811), Anne Carter (1744 – 10 March 1830), and Elizabeth Randolph (1 July 1775 – 3 June 1837).