The 33-year-old half had the ball on a string with his short and long kicking game in front of a crowd of 45,793 at Suncorp Stadium.
Reynolds terrorised the Cowboys' back three in the first half to fire his side to a 20-12 lead at the break.
Fullback Scott Drinkwater and wingers Kyle Feldt and Murray Taulagi dropped floating bombs by the Broncos skipper that led to points.
Reynolds was returning from a medial collateral ligament strain that led to him missing last week's loss to Penrith.
His return gave the Broncos direction and belief in a vital second win for the season.
A highlight of the match was a tackle in the 50th minute by Cowboys co-captain Tom Dearden, who ran the length of the field to tackle Broncos centre Selwyn Cobbo into touch inches from the tryline.
It was a tackle that recalled Scott Sattler's unforgettable effort on Todd Byrne in the 2003 grand final.
Unfortunately for Dearden, his teammates were way off the pace.
Drinkwater let one Reynolds floater bounce in the first half and the game looked up. The Broncos spun it wide for Jesse Arthars to make it 14-0 in as many minutes after hooker Billy Walters had scooted over early.
A pinpoint Reynolds grubber kick set up centre Kotoni Staggs for another try..
The Cowboys were ill-disciplined and kept themselves in the game through individual brilliance
Taulagi flew down the left touchline and kicked infield off the outside of his boot for the ball to land in centre Valentine Holmes's lap for their first try.
Drinkwater genius to step Tristan Sailor and sprint away to score in the corner earned North Queensland their second.
The Cowboys went to sleep at marker in the 54th minute and bench hooker Tyson Smoothy darted over for a 26-12 lead.
Ezra Mam and veteran Corey Oates iced the win with late tries.
The Broncos had previously won only seven of 20 games without representative prop Payne Haas since 2019.
In Haas's absence with a knee injury, lock Pat Carrigan had his best game of the season.
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