King was a close associate of fellow highwayman Dick Turpin; however unlike Turpin, who is often seen by historians a mere rogue, King was the kind of swashbuckling, charming, devil-may-care character into which legend would later transform Turpin. Because of his manners when robbing his victims, King became known as "the gentleman highwayman", and "Captain King".
Turpin and King met on the road one night when the former attempted to rob the latter. King responded with the words: "What, dog eat dog?"
The two joined forces and hid out in a cave in Epping Forest and pursued a successful partnership. One day, however, while visiting a pub, they were recognised and in the chaos that followed Turpin accidentally shot King with his pistol.
King was arrested and later died of his wounds. Before he did, he gave the locations of his hideouts to the constables, perhaps so that Turpin would get caught. However Turpin got away and fled to York where he was later arrested for sheep stealing.
A play titled Dick Turpin & Tom King was written by Victorian playwright W.E. Suter in 1861.