The quest has endured for so long, through years of near misses and frustrating finishes, that the beeper was a popular communication mode when it all began, right here.
Phil Mickelson nearly won the US Open at Pinehurst No.2 in 1999 but was foiled by the late Payne Stewart, who made three big putts over the closing holes to deny Lefty his first major championship and begin an odyssey that has wound its way back to where it started as the tournament returns to the North Carolina sandhills.
As it turned out, had Stewart missed one of those putts, he and Mickelson would have contested an 18-hole playoff - on the day Amanda Mickelson was born.
Which brings us to the beeper.
Mickelson's wife, Amy, was pregnant with the couple's first child and due any day. Mickelson left his Arizona home with every intention of heading right back if his wife went into labour.
"I walked the course on Monday, and at that point I didn't think he was coming," Jim 'Bones' Mackay, Mickelson's long-time caddie, said. "And then he came. He gives me the beeper when he gets out of the car, and he very matter-of-factly told me, 'I don't care when this thing goes off - you tell me - 18th tee on Sunday, first tee on Thursday.'
"He was flat-out going to go home. One hundred percent."
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But Mickelson played - and played well - and finished a shot behind Stewart, who saved par from 15 feet on the final green to win. It was the first of a record six runner-up finishes at the US Open for Lefty.
In 2002 at Bethpage Black, Mickelson could never overtake Tiger Woods, who led from start to finish. In 2004 at Shinnecock Hills, Mickelson was one of just two players to finish under par, but a crushing double-bogey late - coupled with Retief Goosen's extraordinary putting - meant a two-shot defeat.
In 2006 at Winged Foot, Mickelson led by one on the 18th tee, only to hit his drive off a corporate hospitality tent, which led to a double-bogey and one-stroke defeat to Geoff Ogivly. In 2009 at Bethpage Black, a month after Amy's cancer diagnosis, Mickelson couldn't overtake Lucas Glover, who made just one birdie during a Monday finish.
And then there was last year at Merion. That might have been the worst of all. Certainly it's a candidate for toughest defeat. Mickelson was the third-round leader and seemed poised to finally prevail when he holed out for eagle on the 10th hole. But then he made two bogeys before getting to the 18th hole, where, to tie Justin Rose, he needed a birdie on a hole that not yielded one all weekend.
"Heartbreak," Mickelson said afterward. "This is tough to swallow after coming so close. This was my best chance of all of them. I was playing well. I had a golf course I really liked that I could play aggressive on a number of holes. I felt like this was as good an opportunity I could ask for, and to not get it ... it hurts."
Which made his Open Championship victory a month later at Muirfield all the more remarkable.
The Open Championship had always been the major Mickelson was least likely to win. His record was poor, and rebounding from the US Open would, seemingly, be difficult. Mickelson admitted he had spent a few days in bed, depressed.
"I just think it's easier to be honest and upfront about what I'm feeling and going through than it is to try and deny it," he said. "Which is why when I lost, I talk about how tough it is. It's challenging. It was the biggest defeat. I had such a down moment after losing at Merion. It stung."
Yet he bounced back to win the Scottish Open and the Open Championship in consecutive weeks, then immediately embraced the idea of getting the US Open at Pinehurst to complete the career Grand Slam.
"You just do what you have to do to get over it," he said. "I was able to come to the conclusion that I'm playing really good golf, and don't let it affect the potential outcome of some of the upcoming events. That's what really got me to refocus on the future and the upcoming major at the British."
And he has not shied away from the challenge, answering questions ever since about his desire to win the US Open and complete the career Grand Slam.
"When Mickelson had not won a major - remember, he had a lot of failures, a lot of close calls - he said, 'It's not whether I win a major - it's how many I'm going to win,'" said 1993 PGA champion and ESPN pundit Paul Azinger. "I think the fact that he's taking it head-on just fits his personality. Embracing it is one of those things that he does."
Said Mickelson: "There's such a difference in the way I view the few major champions that have won all four. I'm fortunate and honored to be part of that long list of great players who have won three of the four - that's great - but it would mean a lot to me. I would look at myself, I would look at my career, in a whole different light if I were able to get that fourth one."
Only Gene Sarazen, Ben Hogan, Gary Player, Jack Nicklaus and Tiger Woods have won all four of the professional major championships in their careers. Nicklaus and Woods are the only players to do it more than once, having each done so three times. Woods is the only player to ever win four in a row: the 2000 US Open through the 2001 Masters.
Mickelson is among 11 players who have won three of the four majors, but players such as Harold Hilton and Jim Barnes never played in the Masters, and Tommy Armour and Walter Hagen only got a few opportunities, given that the tournament began after they had won the last of their major titles. Byron Nelson played just twice in the Open Championship -- the only major he is missing - and only once during his prime.
The others with one missing major are Lee Trevino (Masters), Tom Watson (PGA), Arnold Palmer (PGA), Raymond Floyd (Open Championship) and Sam Snead (US Open). Snead, like Mickelson, was continually frustrated at the US Open, where he was runner-up four times, including a playoff loss in 1947.
"I'm hoping it'll be easier for him to win now because he won the British last year," Mackay said of Mickelson. "He knew he had to do a lot of work to become competitive in that tournament, and he did. I think he took a lot from that. In a sense, I think that really puts him at ease in terms of his legacy. He proved himself at that tournament last year to be one of the best players to ever play the game."
Mickelson would obviously enhance his standing with a US Open win, a career Grand Slam and his sixth major. Although he says he looks forward to more opportunities, he will celebrate his 44th birthday on June 16, the day after the final round.
A few days later, Amanda Mickelson, the oldest of his three children, will celebrate her 15th birthday - a reminder of how long this journey has endured.
Bob Harig is a senior golf writer for ESPN.com