Having pushed competition leaders Melbourne close last-up before being run over in the final 11 minutes, the Warriors held firm in Auckland to record their fourth win of the season.
The result ended a six-match winning streak for the second-placed Broncos, who played most of the match without NSW State of Origin prospect Peter Wallace.
The halfback left the field late in the opening spell with a recurrence of a groin injury.
Up 24-10 at the break, the Warriors, who had begun the weekend in 12th position, had their line repeatedly tested in the second half, but the second-worst defence in the league showed new resilience.
The contest, played in front of a crowd of 19,012 at Mt Smart Stadium, featured some big hits.
Warriors prop Ben Matulino produced a couple of the biggest, while Brisbane skipper Sam Thaiday soldiered on despite being on the end of two early bone-shaking collisions.
Halfback Shaun Johnson, who scored one of the tries of the season last year against the Broncos, was a key figure as the Warriors dominated the first-half scoreboard.
It was his double-around that created the opening for his side to go ahead through centre Ben Henry.
The Broncos hit back with the double, the first after a Wallace 40-20 set up field position for centre Jack Reed to force his way over.
The second came after Warrior Elijah Taylor conceded a last-tackle penalty that the visitors punished with Alex Glenn dotting down from a slick Corey Norman pass.
However, the Warriors stayed in the contest with some mistake-free football - they completed 17 of their 18 first-half sets - and turned the game around with three tries in 11 minutes.
Two Johnson bombs targeting winger Gerard Beale weren't defused and led to tries for Johnson himself and then Taylor.
Prop Jacob Lillyman, in his first match of the season after an arm injury, then crashed over to get reward for some strong runs after coming off the bench.
The Broncos lifted their intensity at the start of the second half and bench forward Ben Te'o, back from suspension, crashed over to reduce the arrears.
But try as they might, they couldn't get any closer and Warriors back-rower Feleti Mateo effectively sealed victory with seven minutes to go by crossing from close range.
There was enough time for Thaiday to get a late consolation try.
