Littler became a national phenomenon in England with his shock run to the final 12 months ago before being defeated by Luke Humphries.
This time there was no stopping "Luke the Nuke" as he stormed past Dutchman Van Gerwen by seven sets to three.
"I can't believe it," Littler told Sky Sports. "Everyone dreams of lifting this trophy but you have to get through a tough field."
Littler, who posted a three-dart average of 102.7, stormed into a 4-0 lead.
And he showed no signs of nerves to close out the biggest win of his career and the £500,000 ($622,000) first prize in style.
"At 2-0 up I started getting nervous but I said to myself 'just relax'," he added.
"I was throwing for the match but to get it over and done with was special."
Littler's success has inspired a boom for darts over the past 12 months.
His defeat to Humphries 12 months ago was the most-watched sports event, outside football, in broadcaster Sky Sports' 34-year history with 4.8 million viewers.
Littler also came above British prime minister Keir Starmer and King Charles in Google's most searched for people of 2024 in the UK.
"I sometimes say every 17 years a star gets born and he's one of them," said Van Gerwen, who had been the previous youngest winner when he lifted the title in 2014 aged 24.
"Every moment he got to hurt me, he did."
