Few careers are as storied as Bill Belichick's 42-year run.
He started studying football footage and going on scouting trips at the age of 7 with his father, Steve, an assistant coach at Annapolis. He landed his first NFL coaching gig at 21.
Since then, across seven professional teams and five Super Bowl victories, the New England Patriots head coach has gone through every career rite of passage imaginable — from being fired (in Cleveland) to being hailed as a hero (pretty much everywhere else).
And while his story is hardly typical, its many twists and turns have left Belichick with strong views about how to create a successful professional journey — no matter your playing field.
In a recent interview with CNBC at his favorite lunch (and dinner) joint, Mission BBQ, Belichick offered four of his top career lessons for today's young people.
1. Make sure your career is motivated by one thing and one thing only: Love
"If there is something that's your passion when you're young, do it. Let everything else take care of itself," he says. "Don't pick a career for money, or some other reason. Do what you love, because it will never feel like work."
Incidentally, all three of Belichick's millennial children, aged 25 through 31, are pursuing careers in coaching. Sons Stephen and Brian, are with the Pats, and his daughter, Amanda, is the women's lacrosse coach at Holy Cross.
Watch the full interview: Bill Belichick on leadership, winning, and Tom Brady not being a 'great natural athlete'
Belichick was noticeably unenthused when asked what he would have done for a career if football hadn't been an option. Business, he finally replied, without much conviction.
But a bit later, speaking about the path he did take, his intensity revived. "What I love about football is the game," he says, "the speed, the contact, the strategy. That's all combined. It's a brilliant game."
2. Recognize that a talent deficit can be overcome with hard work and self-awareness
OK, so you chase your dream career and find out that, well, you're good, but not especially great, at it. Take heart, says Belichick, from the example of Tom Brady, who, to put it plainly, "is not a great natural athlete ... not even close."
"But nobody's worked harder than Tom," Belichick says. "He's trained hard. He's worked hard on his throwing mechanics, on his mental understanding of the game. He's earned everything he's achieved."
Success, in other words, even becoming an all-time great like Brady, "is not all about talent," says Belichick. "It's about dependability, consistency, being coachable, and understanding what you need to do to improve."
He does add one caveat: If you happen to have a talent deficit, you can never let up in your quest to overcome it. Even with five Super Bowl rings, "Tom still continues to work hard to improve on a regular basis," Belichick says. "That's part of his self-awareness."
3. Have the courage to fight for your crazy-great ideas
Belichick will tell you that one of the defining moments of his career came when he was just 24 and an assistant coach for the 1-4 Detroit Lions. After studying and visualizing a particular formation over and over again, he was convinced it was unstoppable against the team's next opponent, the 4-1 New England Patriots.
There was only one problem: It was an unconventional play, to put it mildly, and he worried that a new coach suggesting a new idea was destined for skepticism, if not worse.
Long story short, Belichick meticulously made the case for the formation to the Lions' head coach — and the team went on to defeat the Pats by three touchdowns in a huge upset.
The lesson, Belichick says, is to get out there with your big ideas. Don't talk yourself out of them, or self-edit, or wait for another day, "just because somebody else hasn't done it, or just because it's not normal.
"If you believe in it, don't be afraid to use it."
4. Put away your social media, and put your energy into building real relationships
He calls them "SnapFace" and "ChatRun" and "InstaBook" maybe as a joke, maybe not. Either way, you can be certain Belichick hates social media, and he says it's for a simple reason.
Success, he believes, comes from relationships with people you know personally, not from strangers who "like" you online. In fact, he traces his own career achievements to the many coaches, football analysts, players, and others in his sport that he took the time to know authentically.
Belichick is famous for having an encyclopedic knowledge of the history of football, and is said to know the game's X's and O's better than any coach who's ever lived. So it's a bit unexpected to hear him talk so ardently about the primacy of relationships.
"In the end, success is more about who you know than what you know," he says. "Because everyone teaches you something. You listen to everyone, and bit by bit, you figure things out."
Again, a caveat: Make sure, Belichick says, you're not just connecting with the people you think might help you, like the "top people and bosses." Rather, he says, "the people who are your peers, or, a lot of the time, the people who are under you, are really, I'd say, the more important relationships."
As for his own career, the 64-year-old Belichick says he has no plans to retire anytime soon. Mention the word "legacy," and you get a look that suggests there are many more seasons ahead.
"That's for another time," he says. "We're on to 2017."
More from Suzy Welch: