Running back Chris Gronkowski #49 of the Denver Broncos during player warm-ups prior to the game against the Kansas City Chiefs at Arrowhead Stadium on November 25, 2012 in Kansas City, Missouri.

ABC | Michael Desmond | Getty Images

But running the business isn't easy — Chris Gronkowski wakes up at 4:30 a.m. to get everything done. Here's what his typical day looks like.

He wakes up early

Gronkowski is up with the sun. After eating breakfast and getting ready for the gym, he takes a minute to "answer a few important emails and check what I have going on for the day," Gronkowski says. Successful business people from Apple's Tim Cook to Ellevest's Sallie Krawcheck famously wake up early, and billionaire Elon Musk also checks important emails first thing.

He exercises

Gronkowski tries to "get to the gym around 5:00 a.m. or 5:15 a.m.," and spends about an hour working out.

After doing strength training and weight lifting, he plays pick up basketball for another hour from 6:00 a.m to 7. Working out is a habit successful people tend to have in common — 76 percent of the rich exercise for at least 30 minutes every day, according to Tom Corley, author of "Change Your Habits, Change Your Life." And billionaires from Mark Zuckerberg to Richard Branson call it an integral part of their routine.

He spends time with his family

From the gym, Gronkowski heads home to for some quality time with his two infant sons and wife Brittany, who is also an entrepreneur, and owns an engraving business called Everything Decorated. "[I] get home before the kids wake up, shower, drink a shake and eat breakfast," Gronkowski says. "[I] hang out with the kids until 8:30 then start working."

Jeff Bezos, the richest person in the world and founder of Amazon, also takes time to have breakfast with his family before he starts his work day.

He makes it home for dinner