Have you ever worked for a "visionary" putting his/her ideas into practice?

"The people behind the visionaries are the ones who truly change the world."

Have you ever worked for a "visionary" putting his/her ideas into practice? It's both exhilarating and challenging.  We have all heard stories about visionaries who are changing the world through CSR and sustainability but you never hear the story of the people behind the visionary who are actually implementing the change.  

Did any of you work for a revolutionary tech wiz, a VC tycoon, public health prophet or a person whose genius can transform CSR? If you have this experience and can share some advice, I'd love to hear from you.