After entering the finals with four losses from their past five games, Trindall's return helped the Sharks hit back in Saturday's elimination final at Allianz Stadium.
Sione Katoa netted a double to help end the season of the Cowboys side he will join next year, while Siosifa Talakai busted seven tackles, scoring Cronulla's opening try, and Nicho Hynes dummied his way brilliantly to the final score.
But the hero of the night was Trindall, who dislocated his shoulder against Canberra just four weeks ago.
The five-eighth spent most of the night awkwardly carrying his right arm, but was barely beaten in defence as the Cowboys unable to pick him out and Teig Wilton the perfect bodyguard.
And while Trindall played with virtually one arm, he at least had his kicking boot.
Twice he forced an error out of Scott Drinkwater with his midfield bombs, with one of those leading to a Katoa first-half try from the ensuing scrum.
With his arm looking slightly more comfortable in the second half, Trindall then put Will Kennedy over for the decisive try with a long ball for his fullback to make it 26-12.
That was Trindall's 31st assist of the year, with no player having laid on more tries in 2026.
Trindall delayed surgery to be fit to play the finals, and while the No.6 didn't look comfortable the good news for Cronulla is he got through the game.
The Sharks will no doubt need him next week if they are to cause an upset against the winner of Penrith or Sydney Roosters.
"His shoulder is good ... it's pretty solid and his strength is really good," coach Craig Fitzgibbon said.
"After a month of footy he was obviously a little bit rusty, but I thought he kicked the ball as well as you can kick a ball.
"Him coming back allows Nicho to run the ball more, and he did that and got his moment too."
For a side with the worst defensive record of any finalist of the NRL-era, the Cowboys did well to hang on as long as they did.
In the first 20 minutes alone Cronulla had 79 per cent of the ball and 22 tackles on the Cowboys' line.
But unlike when they let in 82 points against the Roosters in round 22 and conceded 50 against Canberra last week, North Queensland kept turning up.
Tom Dearden twice denied Jesse Colquhoun close to the line, while Drinkwater and Braidon Burns pulled off a tremendous try-saver on KL Iro.
North Queensland even got back to 12-6 down at halftime through Burns, and 16-12 with 22 minutes to go when Dearden put on a long cut-out ball for Zac Laybutt.
But ultimately the pressure told, and while a late Jaxon Purdue try offered a faint hope the Sharks were never really endangered.
"We were outplayed, but we certainly hurt ourselves," coach Todd Payten said.
"In big games you need to defuse kicks and be clean out of your own end, and we weren't those two things.
"It was a costly night."
The only downside for Cronulla will be the crowd of 17,429, which marked the lowest for a final at Allianz Stadium since 2012.
Officials will no doubt point out that only an extra few thousand fans turned up than would have fit in at Shark Park, had they been able to play there.
Asked if he'd like more fans to turn up next week, Sharks captain Cameron McInnes had simple advice.
"If you can afford it, come. If you can't, watch it on TV," McInnes said.
"I couldn't care less really."
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