George Zimmer has a penchant for speaking his mind.

The 68-year-old serial entrepreneur was fired from Men's Wearhouse, the company he founded 40 years earlier, in 2013 over differences with the company's board.

"You know, one of the very small reasons - and I say small - would be that I tended to be kind of a renegade or somebody who said what he thought," Zimmer told Business Insider about his firing. "That made the board of directors increasingly uncomfortable."

Zimmer has since launched a tuxedo rental company, Generation Tux, and is channeling his candor into marijuana activism.

Zimmer donated $50,000 in 2010 to an ultimately unsuccessful California ballot initiative that would have legalized marijuana for recreational use. He's spoken at cannabis conferences in California and Nevada, two states that fully legalized pot in 2016. This week, he'll add Oregon to the list when he gives the keynote address at the Cannabis Collaborative Conference on February 15.