The 32-year-old American, who grew up only an hour's drive from the famed layout, shook off a history of major near-misses to win the US Open last June at Oakmont, changing his Magnolia Lane mindset.
"You definitely have a different mentality," Johnson said. "Now I'm not going into a major trying to win my first one. I've got one. So it's definitely a nice feeling."
Johnson became world number one with a February victory at Riviera and followed that with triumphs at the World Golf Championships Mexico and WGC Match Play events.
"I've got a lot of confidence now, confidence in my game and in myself," Johnson said. "I just need to keep working hard, keep trying to get better."
The Masters will be Johnson's first major atop the rankings, from which he takes motivation while trying to avoid complacency.
"It's still just a ranking. I don't feel any different," he said. "Being number one, it kind of drives me to work harder and to get better. I still go in every week preparing the same that I always have."
Johnson struggled in his first five appearances but in 2015 became the first player in Masters history with three eagles in one round on his way to sharing sixth.
Last year, he birdied 13 and 15 on Sunday to pull within two of the lead before a double bogey at 17 ended his chance to catch eventual winner Danny Willett of England.
- McIlroy's short game sharp -
Johnson said he likes the state of his game, particularly his trademark long drives, but expect him to be tested by some of the world's best players, including second-ranked Rory McIlroy, 2015 Masters winner Jordan Spieth and five-time major champion Phil Mickelson.
"I'm certainly looking forward to going," said three-time Masters winner Mickelson, whose last victory was the 2013 British Open.
"I feel as though the way I'm playing I could get myself in contention."
Four-time major winner McIlroy, who would complete a career Grand Slam with a Masters victory, is pleased with his game despite a rib injury keeping him to only 10 rounds in March.
"I've worked on my short game. I feel like that part of my game is as sharp as it has been ever going into Augusta," McIlroy said.
"I felt good. I've played well. I can't see a downside to not having played as much as I planned. I feel really healthy."
McIlroy shared seventh at Mexico and fourth at Bay Hill before a group-stage ouster at the Match Play.
"Freshness could help, especially mentally, going in there and not being drained, so that's a good thing as well," McIlroy said.
Spieth meltdown memories linger
Spieth will face mental issues of a different sort. The 2015 champion looked poised for back-to-back triumphs until a back-nine Sunday meltdown last April, a quadruple bogey at the par-3 12th featuring two splashdowns into Rae's Creek dooming his chances and dominating talk this year.
"No matter what happens at this year's Masters, whether I can grab the jacket back or I miss the cut or I finish 30th, it will be nice having this Masters go by," said Spieth, who placed the green jacket on Willett's shoulders.
"The Masters lives on for a year. It brings a non-golf audience into golf. And it will be nice once this year's is finished, from my point of view, to be brutally honest.
"It would be best if I could reclaim the jacket. But I believe I'll be back up there sooner or later, just the way we play the golf course, the success we've had and the comfort level I have there."
It will be the first Masters since the death of golf legend Arnold Palmer, a four-time champion who pioneered golf sponsorship and television deals and who had served as an honorary starter alongside fellow icons Jack Nicklaus and Gary Player.
"Arnold meant an awful lot to every one of us, anyone that's involved with the game of golf in any capacity," McIlroy said. "I think we all owe him a massive debt of gratitude for what he did for the game."