The Australian star claimed the Brisbane Darts Masters title in 2019 and secured a ProTour success the following year after joining the PDC circuit full-time.
He added a further Players Championship title, and the £12,000 prize money, with Saturday's superb success as he denied Anderson in a high-quality decider.
Anderson had won Thursday's Cazoo Premier League night in Nottingham and was in brilliant form throughout Players Championship 5.
The two-time world champion also led 2-1 and 4-3 in the final, having hit a 131 finish in one of two 12-darters, before a mid-game surge from Heta saw him take out 146, 101 and a ten-darter to move 6-4 up.
Back-to-back 14-darters saw Anderson level again, but Heta responded with a 12-darter and punished a miss at tops from the Scot in the next two wrap up victory with a 14-darter on double eight, ending the final with a 107.27 average.
Heta had defeated housemate Dimitri Van den Bergh 7-4 in their semi-final, and also saw off Danny Jansen, Jimmy Hendriks, Keane Barry, Steve Beaton and Daryl Gurney on his way to glory.
Heta hails 'massive' win
"It's massive for me," said Heta, who finished eight doubles from 13 attempts in the final and shared ten 180s with Anderson.
"I knew how well Gary was playing, he was playing sensational darts, but I'm accustomed to the scene now and you've got to take whatever opportunity you've got.
"To win today is massive because I went all last year playing well, I made some finals but not to get a win was a bit disheartening.
"To get a win over another Premier League player is massive for me. I'm always looking up, I've still got everything to gain.
"I don't think I played my best stuff today but I took my chances. I played some decent players that no doubt could win this thing, but I played my own game."
Anderson, meanwhile, looked on course to claim his first Players Championship win since February 2020 after a brilliant run of form on the day.
After averaging 107 in his opening win over Jason Lowe, he then knocked out Michael van Gerwen 6-4 in round two.
The Scot then averaged 109 to edge out Simon Whitlock, 101 against Chris Dobey, 113 in a quarter-final win over Rob Cross and 104 in his semi-final success against Joe Cullen.
Cullen had landed a nine-darter during his third round win over James Wilson, with emerging star Josh Rock also achieving perfection for the first time on the professional circuit in his memorable first round defeat of Dave Chisnall.
The Players Championship double-header in Barnsley concludes on Sunday with Players Championship 6, which will see 128 players competing for £100,000 in prize money.
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