The whirlwind that followed his Masters win finally caught up with him two weeks ago, forcing Johnson into bed with a case of strep throat. Instead of rushing back onto the course, he chilled out at his parents' house in Iowa, caught up on his sleep and practiced a little at the course where he feels the most comfortable.
Johnson surprised everybody but himself when he withstood a Tiger Woods charge to win the Masters in April. Though he'd won in Atlanta as a rookie, had several other solid finishes and was a member of last year's Ryder Cup team, he was never dubbed the next great up-and-comer. He's not flashy -- on the course or off -- and he was one of those guys who could show up at most tournaments without causing much of a stir.
But Johnson put himself in contention with solid rounds in a week that Augusta was wreaking havoc on nearly everyone's game. Then, just as Woods was closing in, Johnson put together three birdies in a four-hole stretch to win.
'Ignorance is bliss, because I didn't know where he was until 15, and I managed to birdie 16,' said Johnson, who was two holes in front of Woods on Sunday at Augusta.
Since then, though, little in Johnson's life has been calm. Or anonymous.
After the Masters, he and his wife flew to New York, where he met with sponsors and hobnobbed with talk-show hosts, including David Letterman. (No. 4 on his Top 10 list of Things I Can Say Now That I Won the Masters: 'I just wrote down `3' for every hole. Nobody checked.')
The very next weekend, he was back on the PGA TOUR, playing the Verizon Heritage.
Most players would have skipped that tournament, and no one would have blamed them. But not only did Johnson show up, he gutted out a sixth-place finish. A month later, he won again, beating Ryuji Imada in a playoff at the AT&T Classic in Atlanta.
Only Woods, with three, has more victories on the PGA TOUR this year. And only the Big Three -- Woods, Phil Mickelson and Vijay Singh -- are ahead of him on the FedExCup list.
'Atlanta, certainly for me, spoke volumes, and it just gave me the reassurance that Augusta was not a fluke,' Johnson said. 'Not that I ever thought it was. But you can get lucky at times. Maybe not a major, but Atlanta was huge in that respect.'
Now everywhere he turns people want just a few minutes with the Masters champ. He's a draw at tournaments -- sometimes the biggest draw -- and what little free time he had before has dwindled even further.
'The only sense of normalcy I've had, for the most part, has been inside the ropes,' he said. 'I like it there.'
By the time he showed up at The Memorial, though, his body had had it. His head was throbbing and his throat was burning from strep. He tried to play, but withdrew after hitting his drive on the 16th hole.
He went back to Cedar Rapids, where he slept and recuperated. He practiced some at Elmcrest Country Club, the course where he grew up playing, but only when his body allowed.
Best of all, he finally got to spend time with his family and friends.
'We had a party for close friends, relatives. And my wife, being the woman that she is, she surprised me and, for the most part, the entire Drake University golf team I was a part of and my coach were flown in,' Johnson said. 'That was pretty cool.
'It was just casual, laid back. Just very much local, very much Cedar Rapids and Elmcrest, where I'm from. It was fun.'
Now it's back to work.
This is only Johnson's fourth time playing a U.S. Open, and he's missed the cut the last two years. But just as he did at Augusta, he's got a game plan for taming Oakmont Country Club. And it includes laying up on those long par 5s.
One of the most notable statistics from Johnson's win at Augusta was he didn't go for a single par 5 the entire week, no matter his distance. That won't be as much of an issue at Oakmont, where there are only two par 5s, but Johnson said he'll lay up on those, too.
'My preparation for this week, it's very much in line with Augusta,' he said. 'Driver is very important. Tee shots are very important, just like it is at Augusta and, for me, wedges. I'm going to miss fairways, so I have to wedge it out and wedge it to the green.
'I think a lot of this golf course is positioning,' he added. 'Giving yourself a chance at par and eliminating double.'