Above is a portrait of Sebright that Francis Wheatley painted around 1770. Sir John Saunders Sebright was born on October 19, 1725, in Flamstead Parish in Hertfordshire, England. He was the second son of Sir Thomas Saunders Sebright, Fourth Baronet, and his mother was Henrietta Dashwood, the daughter of Sir Samuel Dashwood. Sebright began his military career at an early age, obtaining an ensign’s commission in the 1st Regiment of Foot Guards on April 18, 1741. He was promoted to lieutenant and captain on February 20, 1744, and to captain and lieutenant colonel on November 20, 1750. Sebright left the 1st Foot Guards to become the colonel of his own regiment, the 83rd Regiment of Foot, on October 14, 1758. Raised in Ireland for garrison duty, the 83rd was also known as “Sebright’s Invalids.” The 83rd underwent conversion into a line infantry regiment in 1759. Sebright exchanged his colonelcy of the 83rd for that of another of another Irish regiment, the 52nd Regiment of Foot Foot, on November 27, 1760. Promotion to major general came on March 13, 1761. On April 1, 1762, Sebright exchanged the colonelcy of the 52ndFoot for that of yet a third Irish regiment, the Royal Irish.
April 28, 1763, he was elected to the House of Commons from Bath. He would hold that seat from 1763 to 1774, and again from 1775 to 1780. With the death of his elder brother, Sir Thomas Sebright, Fifth Baronet, in 1765, Colonel Sebright inherited the baronetcy. In the following year, Sir John Saunders Sebright, Sixth Baronet, found the time to take a wife. On May 15, 1766, he married Sarah Knight, the daughter of Edward Knight and Elizabeth James, in St. George’s Church, St. George Street, Hanover Square, in London. Sarah would bear her husband five children – three boys and two girls.
The 18th Foot sailed to North America in 1767, but it appears its colonel remained home in England. Such conduct was not exceptional among British regimental commanders at that time, however, and Sir John Sebright received a promotion to lieutenant general on April 30, 1770. He did seem to take an active interest in the regiment and definitely was involved in approving the purchase of officers into the regiment in at least three cases. He made full general more than twelve years later on November 20, 1782. He died at his London home on February 23, 1794, at the age of sixty-eight.