Jack and his wife Sophy were enslaved in Middletown, Connecticut to Philip Mortimer (1710-1794), a wealthy Irish businessman. Philip Mortimer freed them in his will, but his son-in-law, George Starr, contested and succeeded in overturning the will. Mortimer’s will also intended to give Jack and Sophy the use of one and three-quarters acres of land that, upon their deaths, was to be divided between their three sons, Lester, Dick, and John. The three boys were ordered to be kept in school until the age of fourteen, then apprenticed as house joiners until the age of twenty-one, when they were to be freed. In a codicil to his will, Mortimer also left Jack, Sophy, and their sons some kettles and a fishing place in Chatham.
Jack Mortimer’s rage against George Starr for overturning Philip Mortimer’s will in 1796 was immense. Although by 1810 he had gained his freedom, in December 1811 he was accused of “maliciously intending to poison & murder George Starr.” The prosecutor alleged that Jack “did unlawfully & wickedly, solicit, instigate, advise, persuade, & procure Prince [Mortimer]. . . to give & administer a quantity of Arsenic or Ratsbane” to Starr. The case against Jack was inexplicably dropped, but eleven years later, in 1822, he was convicted of arson for burning to the ground a house belonging to Starr’s daughter. Jack was then sentenced to five years imprisonment in Newgate, the first state prison in the United States.