Born on Aldebaran Prime in 2336, he was the son of Kevin and Joanne Thornton, and eventually became good friends with Mark Montgomery and his family. In the early 2360s, he held a teaching position at Starfleet Academy. Montgomery, Timothy Sinclair and Ben Bartholomew were his students, and he would later serve with Sinclair and Montgomery aboard the Christopher Pike. Some time later he married a woman named Heather, and they had at least three children: fraternal twins Colm and McKenna, and Quinn. (PDN: "Children of the Burning Heart", "The Argonaut Syndrome")