Dearden began the series playing second fiddle to starting halfback Daly Cherry-Evans, whose spot he controversially took when Slater dropped the captain for game two.
He finished the series having inspired Queensland to an against-all-odds 24-12 win over NSW in Wednesday night's decider.
Slater called on his Maroons to lift for their captain Cameron Munster after the five-eighth's father died last weekend, and no one rose to the challenge more than his halves partner Dearden.
The North Queensland Cowboy backed the speedy Hamiso Tabuai-Fidow up on a break to score the Maroons' second try, which gave the visitors a three-score lead in the first half.
In defence, he pulled off a try-saving tackle on left winger Brian To'o just as the Blues threatened to make in-roads into the contest during the second half.
Scything over on the right side, Dearden scored the try that confirmed victory and triggered an exodus of Blues fans in the final 10 minutes.
The performance, and his subsequent Wally Lewis Medal, have underlined Dearden's status as the Queensland halfback of the future.
"We had our backs against the wall the whole series, and we really tapped into that Queensland spirit," Dearden said.
"I'm just so proud to be a Queenslander tonight."
