Santoro takes home $449,910 and a $25k seat at the WPT Championship in April for the win. Harder earns $248,962 for his runner-up finish.
The decisive hand came exactly 200 hands into final-table play and just over 100 hands into a back-and-forth heads-up match that started with Santoro grabbing a 7-1 chip edge almost immediately.
After a long battle that saw Harder double up several times and even take the chip lead a few times, the final hand begun with Santoro holding just a slight edge in chips.
Harder min-raised to 160,000, Santoro bumped it to 425,000 and Harder shoved for about 2.5 million over top.
Santoro snap-called with the A♣ K♠ and Harder showed T♣ T♦.
Unfortunately for Harder the board came down J♣ 8♣ 5♠ 2♥ K♣ and his tens couldn't hold on the river.
Despite the epic heads-up match, it looked like it might be a short night at Foxwoods when three players were eliminated in the first 23 hands.
Eli Berg, Andy Frankenberger and chip leader coming into the final table Steve Brackesy were all out before their seats were even warm with Berg going first in hand #3.
Frankenberger followed shortly after in hand #13 and Brackesy was out on hand #23, his A♣ 4♣ failing to catch up with Santoro's Q♥ Q♠.
That left Santoro, Harder and Bob Carbone three-handed but an overmatched Carbone, despite lasting about 70 more hands, would bow out third and leave the two best players to fight to the finish.
The 25-year-old Santoro adds the $449k to an estimated $700k in combined career earnings live and online.
The final six players and their payouts:
1. Daniel Santoro $449,910
2. Christian Harder $248,962
3. Bob Carbone $166,271
4. Steven Brackesy $129,816
5. Andy Frankenberger $99,585
6. Eli Berg $83,580
For a full recap of all the hands played at the final table, check the WPT Live Updates.
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