McIlroy clinched his first championship and third major title with a two-shot victory over Sergio Garcia and Rickie Fowler on a thrilling final day at Hoylake.
And the golfer netted his father, Gerry, £100,000 after he'd placed a bet on his son 10 years ago to win the elusive Claret Jug within the next 10 years at odds of 500/1.
Two friends of Gerry also placed similar bets which will see them collect £80,000 in winnings from Ladbrokes.
The Northern Irishman joins Tiger Woods and Jack Nicklaus as the only players to win three of golf's modern majors by the age of 25.
McIlroy, 25, now just has the Masters left to complete a career Grand Slam.
Starting six clear, McIlroy fired a final-round 71 to finish 17 under as Garcia, who three times got to within two strokes, shot 66 and US Open runner-up Fowler 67.
McIlroy said: "It feels incredible. It wasn't easy - there were a few guys making runs at me and I just needed to stay focused.
"To win three legs of the Grand Slam at 25 is a pretty big achievement."