Rollins shot a Sunday 7-under 65 and then waited as Neal Lancaster (72) inexplicably double-bogeyed the 72nd hole to force a three-way playoff, which also included Justin Leonard (69).
Door ajar, Rollins walked right through by sinking a 20-footer for birdie on the first extra hole to win the Bell Canadian Open.
'I thought it was going to be a tie for second, a great week,' Rollins said. 'We did one better. It's amazing.
'It's a dream come true. Growing up, you always dream of winning. To be part of the champions that have won this tournament is incredible.'
More from Rollins on his win.
Rollins started the day seven back of Lancaster, who led outright for the first 17 holes on Sunday.
Maintaining the two-stroke lead with which he started the round ' after Leonard had bogeyed the 18th ' Lancaster missed the green left at the last. Without hesitation, he snuck his pitch shot onto the putting surface and watched his ball roll down the slope 30 feet from the hole. His first putt raced past the cup. He then missed the five-foot comebacker for the win.
'It wasn't meant to be, I don't guess,' Lancaster said. 'I don't think I'll ever forget that I blew the Canadian Open on the last hole.'
The trio finished regulation at 16-under-par 272.
Back to the 18th they went, where Lancaster again pulled his approach shot, this time into the left greenside bunker. He missed his 15-footer for par and then carelessly rushed his three-foot bogey putt past the hole.
This time, it didnt matter.
After Leonard missed his lengthy birdie putt, Rollins rolled home the winner.
The 27-year-old Virginian became the 13th first-time winner on the PGA Tour this season. He also collected $720,000 to push his yearly earnings to nearly $1.6 million.
This is his second season in the big leagues. He finished 171st on the 2000 money list, thus demoting him to the Buy.Com Tour. Last year, he finished sixth on the developmental tours money list to regain his PGA Tour card.
Rollins made seven birdies and no bogeys Sunday. He seemed primed to earn his best career finish on the primary circuit ' previously a tie for fifth at this year's Honda Classic ' but got a huge gift from Lancaster.
The soon-to-be 40-year-old hadnt dropped a shot since the first hole in Round 2. His grievous mistake 52 holes later, however, cost him his first tour title since the 1994 Byron Nelson Classic.
'I guess I know how Jean-Claude van Damme feels, or whatever his name is,' said Lancaster, who was referring to Jean Van de Velde, whose triple bogey on the 72nd hole at Carnoustie cost him the British Open.
Final results from the Bell Canadian Open