NFL legend Emmitt Smith looks back on the 'youthful financial decision' that cost him $100,000

Retired NFL star Emmitt Smith
CHRIS WILKINS | Getty Images

Hall of Fame running back Emmitt Smith entered the NFL in 1990, when the Dallas Cowboys drafted him 17th overall. His rookie contract came with a $1 million signing bonus. It was around that time when he made one of his more "'youthful' financial decisions," he tells Harrison Barnes in an interview with The Players' Tribune.

"I bought a $100,000 car when I was 20 years old," says Smith, now 49. That's the equivalent of about $200,000 in today's dollars.

"I wanted to treat myself to a convertible Mercedes Benz, the SL. It was burgundy," continues the eight-time Pro Bowler and three-time Super Bowl champion. "Funny story, though. Before I actually bought the car, the car dealers treated me like I couldn't afford the car. I walked onto the lot and I was looking at brand new cars and the sales guy took one look at me — a young African American guy — and he walked me to the used car section.

"He said, 'Uh, let's try to get you into something that you can afford.'"

This NFL starting quarterback drives a dented van he bought from his grandma for $5,000

"He didn't have a clue that I was on the Cowboys. So I looked at what he wanted me to look at, and then I said, 'No, I'll go with the SL. But I'm not gonna buy it from you.' And I went to another dealer and got it there."

While Smith splurged big time as a rookie, he also recognized the importance of preparing for life after football at an early age.

"In my early 20s, I knew I wanted to do something after football, but I didn't know what it was. But as I got to my late 20s, things started to crystallize for me," says Smith, who has built a successful career as an entrepreneur since retiring from the NFL in 2004.

And he picked up some valuable money advice during his years as a Cowboy. In fact, it was Dallas Cowboys owner Jerry Jones who gave him the best advice he's ever received. "He taught me about finances with a simple statement," Smith recalls in an interview with CNBC. "He always said, 'Have a big front door and a small back door. Take in as much as you can, and spend as little as you can.'"

Like this story? Like CNBC Make It on Facebook!

Don't miss: NFL player who lives on $60,000 a year says this book changed his mindset about money

Ex-NFL player and actor Nnamdi Asomugha still drives the 20-year-old car he took to prom