Woodhull was a descendant of Richard Lawrence Woodhull, a wealthy settler of Setauket, and he was also related to New York militia Brigadier General Nathaniel Woodhull. His parents were Judge Richard Woodhull and Mary Woodhull. Woodhull served as a lieutenant in the Suffolk County, New York militia in the fall of 1775 but resigned after a few months. He was motivated by the murder of his cousin Brigadier General Nathaniel Woodhull of the New York militia, who was wounded by sword and bayonet cuts after being captured on August 29, 1776. According to some reports, General Woodhull was deprived of medical care and food and suffered an agonizing death on September 20, 1776, and Abraham Woodhull was inflamed against the British by this event. He did not immediately take up arms or begin spying, however; he was more placid than some of his friends who joined the Continental Army at the outset of the war. He was the only surviving son of aging parents, and he stayed on the family farm to attend to his family and their property.
Spy ring
Continental Army Major Benjamin Tallmadge was Woodhull's neighbor in Setauket. He approached Woodhull in August 1778 about gathering intelligence for the Patriot cause in the American Revolutionary War. Woodhull had been caught smuggling contraband across Long Island Sound, but Tallmadge spoke with Connecticut Governor Jonathan Trumbull and got him released. Tallmadge then set up a spy network in New York with Woodhull as the lead agent. Woodhull began spying in October 1778, sending his first "Samuel Culper" letter on October 29, 1778, after swearing an oath of loyalty to the Crown as cover. His plan was to travel to Manhattan, ostensibly to visit his married sister, Mary Underhill, and her husband, Amos, at their boarding house. While in Manhattan, he would collect information from various sources, including British officers staying at the Underhill boarding house, and then return to Setauket where he could pass the information to Continental Army lieutenant and whaleboat operator Caleb Brewster to take across Long Island Sound to Tallmadge. Tallmadge would then send the information to General George Washington. Austin Roe became the main courier for the ring later, after Woodhull stopped going to New York City to gather intelligence personally. He would deliver messages via dead drop, burying them in a box in a pasture that he rented on Woodhull's property.
After the war
Woodhull married his friend Mary Smith in 1781 and had three children with her. He held a few minor political appointments, including magistrate in Suffolk County, New York from 1799–1810. His wife died in 1806, and he married Lydia Terry in 1824. He died in Setauket on January 23, 1826 and is buried in the Setauket Presbyterian Church and Burial Ground there.
Warren Walker suggested in 1956 that James Fenimore Cooper's character Harvey Birch was based upon "Samuel Culper's" work as a spy. This would include both Woodhull as "Culper Sr." and Robert Townsend, who used the alias "Samuel Culper Jr." Woodhull was portrayed from 2014 to 2017 by Jamie Bell in AMC's spy thriller and historical drama series', based on ' by Alexander Rose. Other people from Woodhull's life are portrayed in the show as well.
