Thomas Harrison was a resident of Tyrrell County. In early July 1777 Daniel Leggett approached Harrison at his home and had him swear two oaths of secrecy and become a member of the Gourd Patch Conspiracy. Harrison later made a deposition stating that Leggett had told him the conspiracy's plotters planned to kill several state officials because of their belief that they planned to introduce Catholicism in the state. Harrison later appeared on a list of witnesses prepared to give evidence against Daniel Leggett before the Edenton District Court of Oyer & Terminer when all the leading members of the plot went on trial in the fall of 1777.