He was an operative at the Department of External Services (DXS), which is where he is impressed by Mac's ingenuity while tracking down Murdoc (Michael Des Barres), an international assassin and master of disguise. When Thornton becomes director of operations at the Phoenix Foundation several years later, he brings MacGyver into the program. In addition to sending Mac out on various tasks for the foundation, Thornton is many times forced to bail MacGyver out of the trouble he gets into.