On live TV Bob Koepka watched his son dominate the golf world.
"Had that feeling right from the beginning that for Brooks, this was his day," he said. "This has been a lifelong dream for him and he has put a tremendous amount of time and effort getting to this point."
Brooks's dad took his son to his first golf course when he was only 3 days old, holding him in his arms as he putted. He had no idea that 27 years later his son would win the U.S. Open trophy on Father's Day.
"It's been a long journey. A lot of great memories. and now he's our national champion. It's a great feeling," he said. I think as a parent, any time you can see your child reach their dreams, you couldn't be happier."
Koepka showed us pictures of little Brooks, picking up golf before he could barely talk.
"That's where he got his first hole in one, at the family golf center on Belvedere. It's not even there anymore," said Bob, pointing at a picture of Brooks when he was 12-years-old.
After graduating Florida State University, Brooks turned pro in 2012.
"Our goal was just make the cut -- and we were just so tickled when he made a cut. And the goals just kept changing and right away, he kept winning and got promoted on the European tour," said Bob.
He left his home to join Europe's minor league tour to get his career going.
"It's a lot of time, a lot of dedication. Brooks has really given it his all, he's very serious about what he does," said Sherri Koepka, Brooks' stepmother.
Brooks's alma mater, Cardinal Newman High School, is beaming with pride.
"We were watching him... get it in! Sink those birdies!" said Jay Lower, Cardinal Newman High School Athletic Director.
The school still has one of his old golf trophies. His picture sits in the Hall of Fame.
"We're happy for Brooks and his achievements. It's exciting! We're very happy on behalf of Cardinal Newman," said Lower.
As for Bob, he got a special call right after the win.
"He just said, 'Happy Father's Day.' He said, 'I didn't get you a card... I hope this makes up for it.' And I said, 'Yeah, you did pretty good son! I'm very proud of you.' I'll give up the card every year for this!"
Brooks's brother, 23-year old Chase Koepka, is also a pro-golfer after a distinguished career at the University of South Florida.
Brooks now lives in Jupiter. Interestingly, his neighbors are fellow golf pros Rickie Fowler, Tiger Woods and Dustin Johnson.