The Currock fighter, 41, got the better of his 29-year-old opponent in a compelling five-round encounter which was shown live on DAZN.
Former British bare-knuckle champion Christie produced a resilient and powerful performance to prevail on points against home-city favourite Thorpe.
It proved a successful returned to gloved action for the former BKFC champion from Carlisle.
His clash with Thorpe was one of the highlights on the Gorilla 2 card – the second major boxing event run by Darren Till’s new promotions company.
The light-heavyweight contest saw Christie playing up to the age difference in the fight, the words “Old Man” emblazoned on his shorts as he took to the ring.
With coach Arron Adair and current Carlisle BKFC fighter Kieron Sewell in his corner, Christie looked to unveil some big early shots but had to show tenacity in the face of Thorpe’s jab.
The Cumbrian, though, began to take the advantage in the third round, rocking Thorpe with some powerful punches, Christie also unmoved as his opponent looked to respond.
Christie then downed Thorpe in round four as he stepped up the barrage while the fifth round saw the boxers relentlessly exchanging punches to the end.
Judges scored the fight unanimously in Christie’s favour with the Carlisle fighter’s arm raised before the two boxers embraced at the end of an impressive contest.