Rahm became the first Spanish player to lift the title and also returned to the top of the world rankings after making birdies on the final two holes at Torrey Pines to finish a shot ahead of Louis Oosthuizen.
The 26-year-old had tested positive for coronavirus just 15 days earlier and was given the news moments after completing a third round of 64 to establish a six-shot lead in defence of his title at the Memorial Tournament.
Given his reputation for fiery displays of temper on the course, that might have been expected to derail Rahm’s bid for victory at Torrey Pines, where he won his first PGA Tour title in 2017 and later proposed to his wife Kelley.
But he handled the situation with an admirable sense of perspective, defending the PGA Tour’s decision to strictly enforce their rules and noting that he still had the positive memories of his performance at Muirfield Village to draw on.
“I know it’s hard to believe, but there’s been a steady progress,” said Rahm. “I feel like from the setbacks, some good moments have come.
“I believe becoming a dad was always going to help me because before I could always have the excuse that getting mad helped me out, helped me win golf tournaments, but right now I’m a role model to my son. I’m going to be, as I am to many kids out there.
“Now I understand what I can do and I know I can perform at my best without showing my frustration so much. I made that deal with myself after the third round of the (US) PGA.
“I wasn’t happy with how I ended, and I could have handled it better, and I vowed to myself to be a better role model for my son.
“He won’t remember any of this because he’s only 10 weeks old, but I do. Hopefully in the future, he can grow up to be someone who’s proud of his dad. I hope I can provide that example.”
Rahm spoke about believing in karma and the “power of positive thinking” following his enforced withdrawal from the Memorial Tournament, which initially meant a 10-day period of self-isolation.
Two negative test results allowed Rahm to leave isolation three days early and he also revealed how messages of support from Ryder Cup captain Padraig Harrington and six-time major winner Nick Faldo boosted his spirits.
“The first person who called me, who wasn’t family, when I was in the isolation trailer was Padraig Harrington,” said Rahm.
“He told me a story in which he was leading by five after 54 holes (in the 2000 Benson & Hedges International Open at The Belfry), and got disqualified.
“He said he learned a lot more than he would ever learn from the win.
“Nick Faldo texted me the next morning and told me a story of how he was winning a tournament. He was leading by six with six holes to go and got disqualified as well, and how he learned from that and got a win the week after.
“I believe from the biggest setbacks we can get some of the biggest breakthroughs, and that’s why I stay so positive. That’s why I kept telling Kelley, when she was devastated about what happened and my family and everybody around me, something good is going to come.
“I didn’t know what, but something good is going to come, and I felt it out there on the golf course and I knew today was my day.”
Jack Nicklaus, who hosts the Memorial tournament, said: “Jon handled what happened at Muirfield Village beautifully.
“His acceptance speech was terrific. What he said about what happened at the Memorial Tournament; how he didn’t blame anyone; and that things like this happen in life. He then shared the story of losing someone close to him because of Covid, so Jon truly knows how dangerous this pandemic has been. He held no animosity after the Memorial.”
Rory McIlroy meanwhile, was determined to take the positives from his US Open performance.
McIlroy was part of a four-way tie for the lead after making a birdie on the fourth hole, but three-putted the 11th and ran up a double bogey on the 12th to effectively end his chances.
“Overall it’s been a positive week,” said McIlroy, whose last of four majors was won in 2014.
“I gave myself a great chance today. Even through 10 holes, I was right in the thick of things. It was really two holes that basically stopped the run at the title.”