1775-1776, Henry William Harrington was a Captain under Col. George Hicks in the Cheraws District Regiment of Militia (SC). He and his company were stationed at Haddrell's Point during the battle of Fort Moultire, SC on 6/28/1776. Later in 1776, he moved his family to Anson County, NC.

1777-1779, Henry William Harrigton was a Captain under Col. Thomas Wade in the Anson County Regiment of Militia.

On 11/25/1779, Henry William Harrington was commissioned as a Colonel in the newly-created Richmond County Regiment of Militia, alongside Col. Charles Medlock who was Colonel/Commandant. Col. Henry William Harrington led the Richmond County Regiment of Militia at the Siege of Charleston, SC and he was captured by the British when Charleston fell on May 12, 1780. He was paroled soon thereafter.

In July of 1780, Henry William Harrington was appointed by the Council of State as Brigadier General (Pro Tempore) to temporarily lead the Salisbury District Brigade of Militia while Brig. Gen. Griffith Rutherford was sent to South Carolina to join up with Maj. Gen. Richard Caswell (NC) and Maj. Gen. Horatio Gates (new Commander of the Southern Department). Brig. Gen. Griffith Rutherford was captured at the battle of Camden, SC on 8/16/1780 and imprisoned in St. Augustine, FL. During his brief command, Brig. Gen. Henry William Harrington seized the town of Cheraw, SC from the British on 12/26/1780 and ordered a POW camp to be erected there.

On 9/5/1780, the newly-created "Board of War" appointed Brig. Gen. (Pro Tempore) William Lee Davidson to take over command of the Salisbury District Brigade of Militia while Brig. Gen. Griffith Rutherford was a POW. No one bothered to inform Henry William Harrington, who was on command in and around Cross Creek and the Pee Dee River area of northeastern South Carolina.

Henry William Harrington learned about Davidson's appointment from his friend, Col. Thomas Wade (Anson County Regiment), and Harrington wrote to Maj. Gen. Horatio Gates asking for guidance, which was not given. Harrington stayed out on command until late December, then he resigned his commission and went home.

Henry William Harrington was born on 5/12/1747, and he died on 3/21/1809. He is buried in the family cemetery at Diggs, Richmond County, NC. Henry William Harrington married Rosa Anna Auld of Anson County, and they had five (5) known children: Harriet, Henry William, Harriet, Michael, and Henry William. The first four all died as infants or in early childhood. The last child survived into adulthood - Henry William Jr. was in the US Navy during the War of 1812 and a member of the NC House of Commons.