Carr was born on January 2, 1770, in Saint James Northam Parish, Goochland County, most likely at the Spring Forest plantation of his parents, Dabney Carr (1743–1773), a lawyer, and Martha Jefferson Carr, sister of Thomas Jefferson. Dabney Carr and Jefferson formed so close a friendship that after Carr’s death, Jefferson took full responsibility for the education of Peter Carr and the younger of his two brothers, Dabney Carr (1773–1837), later a judge of the Virginia Court of Appeals. During diplomatic service in France, Jefferson had to content himself with writing Peter Carr some much-quotedLate in 1794 Carr inherited some slaves and about 500 acres of land in Louisa County. He lived at Monticello until August 1796, when construction projects there caused him to move into Charlottesville. On June 6, 1797, Carr married Esther “Hetty” Smith Stevenson, a widow with one son and the sister of Robert Smith, who later served in Jefferson‘s cabinet, and Samuel Smith, a Maryland congressman. Of the Carrs’ four sons and four daughters, two sons and one daughter died in infancy. After 1798 Carr lived with his family at Carrsbrook, a 900-acre estate about five miles north of Charlottesville that the Carrs initially borrowed and then purchased from while entrusting his informal guardianship to . Carr attended Walker Maury’s academies in Orange and Williamsburg and studied from 1786 until about 1789 at the College of William and Mary and as a private student of . About 1790 Carr began to study law at Spring Forest and Monticello under . He was admitted to the bar in the summer of 1793 but practiced only briefly. , Hetty Carr’s brother-in-law and later governor of Virginia. By the time of his death Carr also possessed 199 acres of adjoining land, at least fourteen slaves, and ten horses.
Carr was a passionate political supporter of Jefferson and the Republican Party, but his first effort to advance their interests failed. Under the pseudonym John Langhorne, heto on September 25, 1797, commiserating with him on alleged calumnies directed at the former in his retirement. After Washington dispatched a , a local Federalist of the subterfuge and charged that Carr had hoped to elicit an indiscreet response. The incident dealt a final blow to Washington’s already deteriorating relationship with Jefferson but otherwise achieved nothing.
Carr’s subsequent political career was more straightforward. After a failed attempt to win election to the House of Delegates in 1799, he supported Jefferson during the 1800 presidential campaign. Carr became a justice of the peace for Albemarle County on April 18, 1801, and about the same time he was elected to represent the county in the House of Delegates. He served three consecutive one-year terms, from 1801 to 1804, and won the same seat a final time for the 1807–1808 session. In all but his third term Carr sat on the Committee for Courts of Justice, and he also served on the Committee of Propositions and Grievances in his first term. He chaired the Committee of Privileges and Elections and served on two minor committees during the 1803–1804 session. Carr lost his bid for reelection in 1808 and was defeated again a year later when he ran for the state senate. A supporter in the latter campaign urged Carr to display less pride and more familiarity with the voters, attitudes that may help explain these failures.
Carr collaborated in the great project of Jefferson’s retirement, the promotion of education. An accomplished student of English literature with an exceptionally melodious speaking voice, Carr in 1811 opened a successful but short-lived academy at Carrsbrook. In 1803 he had been named a founding trustee of the Albemarle Academy, an institution that existed only on paper until March 25, 1814, when he joined four other trustees in an attempt at its revival that included adding Jefferson to the governing board. On April 5, Carr was named president, in which capacity Jefferson wrote him a long and frequently cited, outlining his educational philosophy and urging the board to raise its sights and found a college. The Albemarle Academy Carr helped reinvigorate evolved into Central College and later into the University of Virginia.
Despite his widely acknowledged gifts, Carr failed to realize Jefferson’s hopes for a distinguished legal or political career, at least in part because of the self-indulgence, corpulence, and “extreme indolence” of which he stood accused in an otherwise affectionate memoir by a much-younger cousin. Carr’s notoriety came long after his death with the assertion that between 1795 and 1808 he had fathered at least three sons and three daughters of Thomas Jefferson’s slave Sally Hemings. In 1802, a waspish Richmond journalist, Jefferson of fathering the children. Circumstantial evidence seemed to corroborate the charge. Jefferson was at Monticello when each Hemings child was conceived, and there were no documented Hemings pregnancies during his long absences. Jefferson allowed two of her surviving children to escape from slavery and freed the other two in his , even though he emancipated very few other slaves. Sally Hemings’s son Madison Hemings in the 1870 Ohio census and maintained that Jefferson was his father, an assertion by Israel Gillette Jefferson, another former Jefferson slave.
Descendants of Jefferson’s white daughters, many of his admirers, and some historians sought to refute the allegation. InJefferson’s former overseer Edmund Bacon denied Jefferson was the father of the Hemings children but failed to name another man. Secondhand accounts of two conversations, written in and , reported that Jefferson’s grandson Thomas Jefferson Randolph had fixed the blame on Peter Carr and his younger brother Samuel Carr. One version explicitly named Peter Carr as the father of Sally Hemings’s children, identified his brother as the father of offspring by another Jefferson slave, and described the Carrs shedding tears of remorse about the public furor over Jefferson’s supposed responsibility. In the other, the Carr brothers allegedly found their uncle’s predicament amusing, and in relating the story Randolph’s sister concluded that Samuel Carr was responsible. From the initial publication of the first of these accusations in 1951, most Jefferson scholars, despite the absence of any contemporary evidence naming the Carrs or placing them at Monticello at the critical times, accepted these later, obviously contradictory stories as exculpatory of Jefferson and speculated on whether Peter Carr or Samuel Carr, both of whom lived reasonably close to Monticello, was the father. Samuel Carr probably did form other interracial sexual liaisons, but he had been raised by relatives in Maryland and seems to have been much farther removed from Jefferson and the Monticello social circle as an adult. Peter Carr was therefore often accepted as the likely father of the Hemings children until the publication in 1997 of Annette Gordon-Reed’s monograph Thomas Jefferson and Sally Hemings: An American Controversy, which made a strong case for Jefferson’s paternity. The following year a DNA analysis conclusively ruled out both Carrs, established Jefferson or a male-line relative as the father, and, in conjunction with the other evidence, suggested Jefferson himself was the most credible candidate.
After a British army burned Washington in August 1814, Carr joined the contingent of militia guarding the approaches to Richmond. The British moved instead against Baltimore, and he returned home, but the rigors of service in a hastily constructed encampment undermined his already delicate health. Two weeks after complaining to Jefferson of rheumatism, ague, and fever, Peter Carr died at Carrsbrook on February 17, 1815. As he had requested in his will, he probably was buried near his parents and children in the family cemetery at Monticello, but no gravestone survives.