The 7x Super Bowl champion penned the forward for his mentor's book in just three days, Harden tells PEOPLE exclusively
When Tom Brady was 18, he began working with life coach, motivational speaker and executive consultant Gregory Harden. Nearly three decades later, the seven-time Super Bowl champion has penned the forward to Harden's book, Stay Sane in an Insane World: How to Control the Controllables and Thrive.
In an exclusive interview with PEOPLE, Harden, 52, details Brady's "fascinating transformation" over the years and how their relationship helped the quarterback find the perseverance to become one of the greatest athletes ever.
Brady was, according to Harden, "a snot nose that just got off the boat" when the two first met, he says. "He was struggling and trying desperately to be a starting quarterback," recalls Harden, who has also mentored the likes of Desmond Howard and Michael Phelps.
"I think he shared with me that he saw what Desmond Howard and I had done. Desmond ended up winning the Heisman Trophy and boom, boom, boom. Tom said, 'Hey, maybe you could support me. Help me a little bit.' So, we started working," Harden explains.
"So to me, Tom Brady is a 18-year-old who I met, who turned out to be that dude," he says with a smile.
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Harden worked with Brady for years, even after he became a star in the league, navigating not just his mindset on the field but his ability to disconnect from the demanding lifestyle of his celebrity.
"By the second and third Super Bowl, he has no life," Harden recalls. "He can't go outside. He can't go to the store. He can't go get a soda pop."
Before he became the household name he is today, Brady "wanted to be the absolute best, but he didn't want to be a star," says Harden. "So for him, it was overwhelming in the beginning. It's difficult to manage all of that when that's not your dream."
A young Brady's dream, according to Harden, "was to be the absolute best competitor and teammate," but "stardom was not his mission."
Harden taught Brady his foundation for success, which Brady praises in the forward of the book. "For him to still, after all these years, be willing to give me any credit for what the foundation was, it's humbling," says Harden. "The foundation was him training himself to give 100%, 100% of the time, training himself to trust and believe. If no one else believes in you, to believe in yourself."
The wisdom from Harden that helped catapult Brady into superstardom is laid out in the book, the author promises. "Those are the lessons that are in the book — Tom made it crystal clear to anyone that listens, that you have to allow somebody inside."
The book, available August 15, isn't about Harden. It's about his mentees, says the author. "It's really about the work and seeing people transform."
Harden adds, "What's magnificent about the life I've led is watching someone go from a snot-nosed little brat to an adult, to a seasoned veteran, turning themselves into someone who can do what the average person dreams of doing. So, what I hope people will take away from the book is training themselves to give 100%, 100% of the time, at everything they do."
There's a catch though, says Harden. Giving your all to everything "isn't possible" all the time, which is why the key to Harden's wisdom is in his clients trusting themselves and their work.
"You can't give 100%, 100% of the time. What you can do is have that as your default mode," Harden explains. "So, what I try to teach anyone that will listen, is pretty straightforward, 'My default mode is 100%, 100% of the time. My worst day is going to be better than the average person's best day.' "
Brady wrote the forward for Harden in just three days, the author tells PEOPLE. "I thought maybe Tom could write the forward, I asked him, and three days later, Tom has written the forward, and everyone's mind is blown."
Harden says he and Brady don't talk often now that the quarterback is retired, but when they do, "it's about something important." He adds, "That's one of the nicest relationships I have with a so-called megastar."
Because of his work with Brady, Harden says he gets asked "one silly question" all the time. "Hell no, I didn't know Tom Brady was going to be Tom Brady. Tom didn't even know he was going to be Tom Brady!"
Stay Sane in an Insane World: How to Control the Controllables and Thrive is available on August 15 in stores and online.
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