Victor Charlet fired in the opener for France before half-time at Stormont and Shane O'Donoghue levelled from a short-corner as it finished 1-1.
Ireland's Conor Harte, Eugene Magee, Lee Cole and Johnny McKee scored in the shoot-out while David Harte's pair of saves ensured a 4-2 victory.
Ireland had already qualified for World League 3 by finishing in the top three.
The first half of the final was a subdued affair with flowing hockey at a premium.
France earned a couple of short corners that Harte kept out while his counterpart Arthur Thieffry did likewise, saving from O'Donoghue and McKee.
With the half petering out, France won their third short corner and Charlet netted with a low bullet down the middle.
The third quarter provided more of the same before Ireland stirred in a big way in the closing quarter, rattling the French who were reduced to nine men for various indiscretions.
Gormley won Ireland's only short corner which O'Donoghue nailed with eight minutes to go.
Jonny McKee and Lee Cole then both stung the palms of Arthut Thieffry in a rousing finale before the game was decided by a shoot-out.
"It was a good battle - France played really well, controlled the ball nicely but I knew if we could get our press going, we could put pressure on them," said Ireland coach Craig Fulton.
"It was a tough game. The last 20 minutes, the intensity started to liven up.
"We knew we would create something and the last quarter turned in our favour when they got the two green cards and the yellow which opened the gate for us."
Scotland clinched a spot in World League 3, where the 2018 World Cup places will be decided, by beating Wales 4-0 in the third/fourth place play-off.
Ireland beat France in a penalty shoot-out to secure victory in the World League 2 final in Belfast on Sunday.