Here's what Kobe Bryant thinks professional athletes should do after retiring

Despite earning more money in one season than most of us do in a lifetime, many professional athletes struggle with their finances.

NBA All-Star Antoine Walker, for example, made more than $108 million over his 12-year career but ended up filing for bankruptcy two years after retiring from the league.

"Unfortunately for us athletes, retirement age is 32, 34 — if you're lucky, 37 like myself," five-time NBA champion Kobe Bryant told CNBC .

"Once you retire, you don't have that source of income that's coming in. Even if you save over a 15-year career, if your spending habits remain the same, eventually the well will run dry."

That's why Bryant believes it's crucial to think about what comes next, but he doesn't think athletes should consider only the most lucrative path.

He said: "The question needs to be, 'What is my passion?' Not, 'Where can I create the most value or generate the most revenue?' — but, 'What is my next passion?' When you find that next passion, everything else will make sense."

Bryant, who retired from the NBA last season after a 20-year career with the Los Angeles Lakers, has found his next passion: investing in entrepreneurs.

He and his partner Jeff Stibel — who have already invested in 15 businesses together since 2013 — recently unveiled a $100 million venture capital fund, which they'll use to invest in technology, media, and data companies.

"Jeff and I have quietly been building this for four years and getting a chance to learn each other, but also learn the business and see if I actually love it," Bryant told CNBC. "I have to tell you, there's no greater feeling than actually helping entrepreneurs be successful and being a part of something that's actually helping their dreams come true. There's no greater feeling."