"Like I always said winning feels so good, but the memories and friendships made, nothing compares."
Terrence Ruffin finished first in the Arnold Classic Physique component of the event, Missy Truscott won the Fitness International award and Jennifer Dorie took home the trophy in the Bikini International competition.
Schwarzenegger, the bodybuilding icon who transitioned into an acting career in Hollywood before turning his hand to American politics, was on hand to present some of the awards.
"Congratulations to all of the winners at this year's @arnoldsports classic! You are all true champions, and I look forward to seeing you guys very soon," he wrote on social media.
Walked picked up a winner's cheque worth $AUD180,000 for his troubles but there's no time to rest. He'll be back in action early in October at the Olympia Fitness and Performance Weekend.
In addition to the Arnold Classic title, Walker also took home the Most Muscular award.
He only turned professional last year and also won this year's 2021 New York Pro before continuing his hot streak at the Arnold Classic.