After retiring from the NFL in March 2015, former San Francisco 49ers linebacker Patrick Willis found his second act at a small tech start-up.
On the outside, the two worlds couldn't seem more different.
He traded a football for a Mac laptop, cheering fans for a quiet office. But for Willis, football and the start-up life have a few surprising similarities.
"It's all about becoming one," Willis told CNBC.
Both sports and business are about "putting together a good team to work together and be on the same page to accomplish great things together," he said.
In his new role, Willis is EVP of strategic partnerships at Open Source Storage, a start-up specializing in cloud technology. He handles multiple parts of the business, including hiring and firing.
"That's one thing that's been really fun here — cultivating a good environment and good workmanship," Willis said.
But it's not all fun and games. Just like being a pro-athlete, working in Silicon Valley requires hard work.
"You know, being in a start-up — it's a grind," he said. "It's a grind every day and every day for sure in sports. There [were] no easy days, at least I didn't feel like there were."
Open Source Storage CEO Eren Niazi only has good things to say about his new employee.
"I'm a really good judge of character, and one thing I can say about Patrick is that he works really hard," Niazi said. "He comes in the office and gives 110 percent, and he's honest. That's what you need in order to succeed."
Of course, there have been some big changes for Willis since leaving the football field.
Instead of learning plays and then executing them physically, in the start-up world "you're learning it all mentally," he said. It's a different kind of performance.
But his best advice holds true for both sports and business.
"If you have your mind set on something and you truly believe in it, then you work on it with all your might," Willis said.
See also: Ex-NFL player Patrick Willis: What leaving football for Silicon Valley taught me
Video by Jeniece Pettit.