Smith dominated the showpiece at the MVM Dome in front of a record crowd of almost 6,000 people.
The Englishman took a 2-1 lead with 103 and 124 checkouts before winning five successive legs to move within two of the title.
He finished the match with an 11-dart break of throw, averaging 101 and converting 73% of his attempts at double.
“I feel a bit in disbelief in a way because I was coming here on the back of two losses in the World Series,” said Smith, who moved up to world number 15 after collecting the £35,000 top prize.
“It’s Gary Anderson, isn’t it? He’s a legend. To be able to beat Gary, wow."
Smith also moved to the top of the 2026 European Tour rankings, ahead of fellow two-time champion Wessel Nijman.
“At the end of the day, I’m playing in front of thousands and thousands of people,” Smith added.
“This is my job, wow! I’m so grateful, it’s a pinch-myself moment. I absolutely love the European Tour. To travel the world and see everything, and take my little lad with me, it’s an absolute privilege.”
Anderson ended the weekend as runner-up, but strengthened his European Championship hopes after recording his first four European Tour wins of the year.
The Scot began with a 6-2 victory over Krzysztof Ratajski, averaging 105.27, before edging Stephen Bunting in a deciding leg.
Anderson then beat Gian van Veen in another last-leg shootout before surviving five match darts against Nathan Aspinall to reach the final.
“I ran out of steam a long time ago!” Anderson joked afterwards.
“Making the final was sheer luck. It was a gift from the gods I got this far.
“Ross has been brilliant throughout the day. We watched him during the second game, he was fantastic.
“We’ve got a few tournaments left to get into the Finals, so I’m going to give it my damnedest.”
The European Tour returns next weekend with the Czech Darts Open in Prague from 4th to 6th September.
Results
Afternoon session
Round three
Dirk van Duijvenbode 6-4 Rob Cross
Danny Noppert 6-4 Ryan Searle
Ross Smith 6-4 Jonny Clayton
Dave Chisnall 6-2 Keane Barry
Gian van Veen 6-3 Jermaine Wattimena
Gary Anderson 6-5 Stephen Bunting
Nathan Aspinall 6-4 Michael van Gerwen
Chris Dobey 6-3 Josh Rock
Evening session
Quarter-finals
Danny Noppert 6-5 Dirk van Duijvenbode
Ross Smith 6-2 Dave Chisnall
Gary Anderson 6-5 Gian van Veen
Nathan Aspinall 6-5 Chris Dobey
Semi-finals
Ross Smith 7-3 Danny Noppert
Gary Anderson 7-6 Nathan Aspinall
Final
Ross Smith 8-2 Gary Anderson