Playing many sports as a youth (baseball, basketball, football, and soccer), Johnson took up golf at age 10 and developed his skills at Elmcrest Country Club.

He played number-two on the Regis High School golf team and led them to an Iowa 3A state championship in 1992, his sophomore year.

As the number-two player on the Drake golf team, he led the Bulldogs to three NCAA regional meets and two Missouri Valley championships.

Johnson won his first PGA Tour event in 2004 at the BellSouth Classic outside of Atlanta, one stroke ahead of runner-up Mark Hensby.

In April 2007, Johnson won his first major title at the Masters Tournament in Augusta, Georgia, two strokes ahead of runners-up Tiger Woods, Retief Goosen, and Rory Sabbatini.

After winning, he mentioned his Christian faith and thanked God, saying: "This being Easter, I cannot help but believe my Lord and Savior, Jesus Christ was walking with me.

Other highlights in 2009 include a tie for 2nd place at the John Deere Classic and a solo 3rd-place finish at the Arnold Palmer Invitational.

In 2010, Johnson started the season solidly on the PGA Tour, making ten of his first eleven cuts without any significant results.

Johnson only missed two cuts all year en route to qualifying for the season ending Tour Championship and the 2010 U.S. Ryder Cup team, his second appearance in the event.

It did not affect the outcome, with the only difference being Johnson signing for a double-bogey instead of a par on the final hole, and winning by a single stroke over Jason Dufner.

[14] At the 2012 Open Championship, played at Royal Lytham & St Annes Golf Club in Lancashire, England, Johnson finished at even par for the tournament (280), tied for ninth, seven shots behind winner Ernie Els.

[17] With the win, Johnson moved up to 7th in the Official World Golf Ranking, and claimed a career high 6th due to 8th place in the following week.

[19] He became only the sixth golfer to win majors at Augusta and St. Andrews, the others being Sam Snead, Jack Nicklaus, Nick Faldo, Seve Ballesteros, and Woods.

[23] In July 2021, Johnson was forced to withdraw from 2021 Open Championship after testing positive for COVID-19, ending his streak at participating in 69 consecutive majors.

He has stated: "This Foundation will fulfill a dream of mine and Kim's to give back to Cedar Rapids in a long-lasting, meaningful way.

QF, R16, R32, R64 = Round in which player lost in match play "T" = tied Note that the HSBC Champions did not become a WGC event until 2009.