The 30-year-old thrived at Willards Beach as he capitalised on the best swell of the waiting period in an action-packed day of world-class surfing to beat the 27-year-old American in the showpiece.
Hall held his composure throughout the 35- minute final, opening with an excellent 8.33 (out of 10), waiting until the final minute to seal his win.
He pipped Curran with his 6.67 back-up ride, winning the heat by 15.00 to 13.67 (both out of 20.00).
“It’s the biggest win of my career by far,” Hall said. “I kind of felt like if you’ve got the wave out there you could get the score and I was just praying for a wave at the end.
“Nathaniel is an amazing surfer and I was pumped to have a final against him. It was always going to be a tough heat but I’ve learned never to be content with second and to always push for more until you’ve won.”
Hall’s victory comes off the back of a stellar competitive season in which he won in China and was a runner-up at the ASP Prime Lowers Pro at Trestles, California.
Hall’s consistency has seen him rocket up from 27th to 16th on the world rankings.
“It’s still a long road ahead and I’m just going to keep trying and see where I end up,” Hall said.
“I’m not doing JBay and I’m proud of my choice. I came here and put all eggs into one basket because if you are here to qualify it’s about the Primes. That’s my focus so I’m taking it to the next event in America.”
1 - Glenn Hall (IRL) 15.00
2 - Nathaniel Curran (USA) 13.67
Heat 1: Nathaniel Curran (USA) 12.10 def Adriano De Souza (BRA) 11.00
Heat 2: Glenn Hall (IR) 14.67 def Nat Young (USA) 14.50
Heat 1: Nathaniel Curran (USA) 11.60 def Travis Logie (ZAF) 10.83
Heat 2: Adriano De Souza (BRA) 17.33 def Brian Toth (PRT) 5.73
Heat 3: Nat Young (USA) 15.00 def Jordy Smith (ZAF) 12.00
Heat 4: Glenn Hall (IR) 10.44 def Jack Freestone (AUS) 9.90