Dugan joins San Francisco 49ers recruit Jarryd Hayne and current captain Paul Gallen as winners of the prestigious award.
The medal is awarded annually to the best Blues player in the State of Origin series as voted by NSW players and coaching staff.
"Josh was outstanding over the course of the series and fully deserves this prestigious award," Blues coach Laurie Daley said.
"He was our most consistent performer over the three games and I'm happy to see his efforts being recognised.'
NSW front-rower Aaron Woods won The Daily Telegraph People’s Choice Award, chosen by Blues supporters.
Vice-captain and unwanted Wests Tigers skipper Robbie Farah won the True Blue Award 'for displaying qualities upon which the team culture is built'.
Farah missed Origin III with a broken hand but played Game 2 with a painful rib injury.
"Robbie has a special kind of resilience and toughness," Daley said.
"He played the majority of game one under duress and was an important member within the squad in the lead-up to game three."