Sullivan was over the moon when he won a trip to space with an ace during the KLM Championship last here, but having his name on the world’s second oldest Open trophy means more than anything else he has achieved.
“To see the names on the trophy and to know that my name is going to be on that trophy forever, is just unbelievable,” he said. "To just play on The European Tour is something I've wanted to do my whole life, so to win an event just caps it all.
Sullivan and Schwartzel squared off on 11-under-par 277 after Sullivan posted a 67 and the South African squandered a five shot lead to sign for a 74 in regulation play.
The pair returned to the 18th tee for the sudden-death play-off.
Sullivan’s tee shot landed in the left rough in a grove of trees, while Schwartzel posted his well right of the fairway. Schwartzel could only a sideways shot to the fairway out of the brutal rough, but Sullivan aimed straight for the grand stand and pulled off a magnificent approach from 131 meters that landed 12 feet from the hole.
Schwartzel hit his approach within a foot of the flag, but Sullivan showed none of the pressure he felt and nailed the birdie putt to secure his first European Tour win.
Schwartzel took a five shot lead into the final round and, despite some errors, still held a four shot lead with five holes to play.
He failed to get up and down from a plugged lie in a greenside bunker on the 14th and ran up a six at the par-four 16th with a three putt. The former Masters hit a poor tee shot at 17 that led to another bogey and saved par at the 18th to force a play-off with Sullivan.
"It's unbelievable," the 28-year-old Nuneaton professional said. "After Saturday I didn't think I stood much of a chance with Charl getting ahead that far.
"I just dug in there yesterday and today and found myself in a position where I had a chance to win,” said the first English champion of the world’s second oldest Open since Tommy Horton in 1970.
“My caddie said over the last few holes 'no regrets' and I've definitely got no regrets over the last few holes, especially that play-off hole.
"Charl has won Major Championships. My caddie said “expect him to hole his third” and he nearly did. I was delighted just to hit the green and have a chance to win and I'm just glad I took it.
"That was the most nervous I’ve ever felt over a putt, but I didn't want to give him a second chance to take the title away from me. I am absolutely delighted and I hope the guys at Nuneaton Golf Club are having a few beers for me!
England's Lee Slattery carded a closing 69 to finish third, just one shot outside the play-off, while Spain's Pablo Martin also carded a 69 to finish a further stroke back in fourth.
European Tour winner Thomas Aiken and Jared Harvey finished in a six-way tie for fifth on seven-under-par 281 after Aiken carded a closing 70 and former SA Stroke Play champion Harvey signed for a 71.