Sumner was born in Nansemond County, Virginia, United States in 1733, where his grandfather, William Sumner, had become a freeholder about 1691. He was born to Jethro and Margaret Sullivan Sumner. His family had originally settled in Nansemond County in 1691.
With a fair education, military experience, business acumen, handsome physique, native ability, and attractive personality, Sumner rose to local prominence as justice of the peace in 1768 and as sheriff, 1772-77.
Sumner served from 1755 to 1761 in the Virginia militia during the French and Indian War, rising to a lieutenancy and to the command of Fort Bedford in 1760.
She brought him a large inheritance and he established himself as a tavern-owner and planter at the seat of Bute (later Warren) County. With a fair education, military experience, business acumen, handsome physique, native ability, and attractive personality, Sumner rose to local prominence as justice of the peace in 1768 and as sheriff, 1772-77.
He represented Bute County in the revolutionary provincial congress of August-September 1775, which elected him major of the minutemen of Halifax district. In November he went to the aid of the Virginia patriots near Norfolk; and, following his election on April 15, 1776, by the fourth provincial congress as colonel of the third battalion of North Carolina continentals, he marched first to the lower Cape Fear, thence to aid in the successful defense of Charlestown in June.
Later he joined Charles Lee, 1731-1782, on the projected expedition against Florida, but left it at Savannah in September to return to North Carolina for supplies. He led his battalion northward in the following spring and served in Washington's army through Brandywine, Germantown, and Valley Forge, until illness in the spring of 1778 compelled his return to North Carolina.
During the summer he recruited for the continental battalions. Elected brigadier-general by the Continental Congress on January 9, 1779, Sumner led a brigade of newly recruited continentals to South Carolina and participated in the battle of Stono Ferry on June 20.
For more than a year from July he was recruiting the North Carolina battalions. As commander of a brigade of militia in the southern piedmont region he assisted in the gallant defense of North Carolina against Cornwallis' invasion in the fall of 1780 until, in October, piqued by the elevation of General Smallwood to the command of the state forces, he declined further militia service.
However, at General Greene's request, he offered his services again in February 1781; but General Caswell did not give him a militia command.
Again he endeavored to raise troops until July, when he reinforced Greene with a brigade of three small battalions of raw continentals, who fought like veterans at Eutaw Springs on September 8. During the remainder of the war, he was in charge of military forces in North Carolina. In 1783 he retired to the supervision of his tavern, his plantations, and his three minor orphan children.
On April 18, 1784, he presided at the meeting of the North Carolina Society of the Cincinnati in Hillsboro. With his strong constitution undermined by the exposures of war, he died at his home in Warren County between March 15 and 19, 1785.
He died in 1785 with extensive landholdings and 35 slaves.
Jethro Sumner served with distinction in the battles of Stono Ferry and Eutaw Springs. His creditable, varied, and continuous service throughout the war ranks him among the foremost of North Carolina patriots in the Revolution. After the end of the war in 1783, Sumner helped to establish the North Carolina Chapter of the Society of the Cincinnati, and became its first president. His possessions included approximately 20, 000 acres and thirty-four slaves.
He was a member of the North Carolina Chapter of the Society of the Cincinnati.
Sumner was a brave and reliable officer, considerate of his soldiers, and a good disciplinarian.
He married to Mary, the daughter of William and Christian McKinnie Hurst, of Granville County.
His daughter, Jacky Sullivan Sumner, became the wife of Thomas Blount.
