Born in Boston, Massachusetts on June 18, 1757, he was the son of wealthy merchant and political figure Royall Tyler (died 1771) and Mary (Steele) Tyler. He attended Boston Latin School and Harvard University, where he earned a reputation as a quick-witted joker. His roommate at Harvard was Christopher Gore.
In Braintree Tyler lodged with Mary and Richard Cranch. Mary Cranch was the sister of Abigail Adams, and Tyler soon met John Quincy Adams, with whom he became friendly, and Abigail ("Nabby"), whom he courted. Tyler had developed a reputation as a profligate while in college, supposedly squandering half his inheritance on parties, in grog shops and pursuing women after the death of his father. In a letter to her husband John Adams, Abigail noted that despite having "a sprightly fancy, a warm imagination and an agreeable person," Tyler was "rather negligent in pursueing (sic) his business ... and dissipated two or 3 more years of his Life and too much of his fortune to reflect upon with pleasure; all of which he now laments but cannot recall." John Quincy Adams apparently enjoyed Tyler's company, but questioned his integrity and did not think him suitable marriage material. Nabby Adams eventually ended the relationship, to the approval of her parents and brother.
Tyler served again in the militia in 1787, as aide de camp to Benjamin Lincoln during the suppressing of Shays's Rebellion. After the rebels fled he was dispatched to Vermont to negotiate for the arrest of the rebels.
Tyler was friendly with Joseph Pearce Palmer and Palmer's wife Elizabeth Hunt, and resided in their Boston boarding house. In 1796 Tyler married their daughter Mary, who was eighteen years younger, and they moved to Guilford, Vermont. They moved to Brattleboro in 1801, and were the parents of eleven children: Royall (Born 1794, died in college); John (b. 1796); Mary (b. 1798); Edward (b. 1800); William (b. 1802); Joseph (b. 1804); Amelia (b. 1807); George (b. 1809); Charles Royall (b. 1812); Thomas (b. 1815); and Abiel (1818-1832). Several Tyler children had prominent careers, including four who became members of the clergy.
Mary Palmer Tyler lived to age 91. She died in Brattleboro on July 13, 1866, and was buried next to her husband.
A Federalist, Tyler served as Windham County State's Attorney. In 1801, he was appointed a Justice of the Vermont Supreme Court, even though the Vermont House of Representatives was controlled by the Democratic-Republican Party. In 1807 he became Chief Justice, and served until 1812.
From 1811 to 1814 Tyler was a Professor of Jurisprudence at the University of Vermont.
From 1815 to 1821 he was Windham County's Register of Probate.
In 1787, his comedy The Contrast was performed in New York City, the first American comedy to be performed by professional actors. The play's first public showing was shortly after George Washington's inauguration and Washington and several members of the First Congress attended. The play was well-received, and Tyler became a literary celebrity.
Tyler continued to write, and frequently collaborated with his friend Joseph Dennie, including co-writing a satirical column which appeared in Dennie's newspaper The Farmer's Weekly Museum. He published The Algerine Captive in 1797 and wrote several legal tracts, six plays, a musical drama, two long poems, many essays, and a semifictional travel narrative, 1809's The Yankey in London.
In later life Royall Tyler admitted to his youthful arrogance and profligate conduct, but said he regretted only the limitations which his past placed upon his career and later ambitions.
He was believed to have fathered a child with Katharine Morse, the cleaning woman in the Harvard College buildings when Tyler was a student. This son, Royal Morse, was born in 1779 and came to public attention as a leader of the 1834 anti-Catholic riots in Cambridge.
According to Palmer family descendants, Tyler fathered one daughter, and possibly two, with his landlady and mother-in-law Elizabeth Palmer while her husband, Joseph Pearse Palmer was away. The girls were Sophia, born in 1786, and Catherine, born in 1791.
Tyler was accused[by whom?] of starting a sexual relationship with Mary Palmer before she was old enough to marry. In her version of events, her neighbors believed that she was pregnant before she married Royall Tyler because the neighbors didn't know that they had married in secret.
Tyler has been identified as the model for Jaffrey Pyncheon in Nathaniel Hawthorne's The House of the Seven Gables. Hawthorne's wife was a descendant of Elizabeth Palmer. The Palmer family preserved stories of Tyler's sexual misbehavior as a young man, some of which were known to Hawthorne, and which he used in his novel.