Russell Westbrook's best days are behind him on an NBA court, but the Los Angeles Clippers star is confident he still has a bright future off it.

The nine-time All-Star told Forbes' Matt Craig he wants to attain billionaire status "sooner than later."

"My mantra is 'Why not?' I live by that," he said. "It took 75 years for somebody to average a triple-double. Well, I did it four times."

Westbrook has earned $336.4 million over his NBA career along with around $200 million more in endorsements and business investments, per Craig. His overall net worth is pegged at $375 million.

In order to become a billionaire, the 34-year-old will likely have to count on his non-NBA earnings to climb significantly. After getting bought out by the Utah Jazz this season, the door might already be closed on him continuing to cash in with lucrative multiyear contracts.

Craig wrote Westbrook has his own streetwear brand, Honor The Gift, but that Russell Westbrook Enterprises (RWE) is where the foundation of an empire could be laid.

RW Digital, a digital advertising business launched by the 2016-17 MVP, has a number of notable commercial partners and is expected to generate $37 million in revenue. Through RWE, he's also exploring a foray into the automotive parts industry.

"It's not a sexy business by any means, but it's a very lucrative business that grows exponentially," Westbrook said to Craig. "It clicked for me in my brain. It's like, non-sexy is sexy for me."

Craig estimated that a portfolio similar to Westbrook's could require almost 20 years to hit a $1 billion valuation.

The skills required to become an elite basketball player are certainly much different than the ones for success in business. But Westbrook's dogged determination is one reason why he put himself on a Hall of Fame trajectory in the NBA, and it will serve him well in his next career.