What Entourage's Adrian Grenier learned from billionaire Michael Dell

Adrian Grenier, the actor and filmmaker best known for his roles in HBO's Entourage and The Devil Wears Prada, thinks that entrepreneurship can change the world.

It's something he knows a little bit about: In addition to his career in show business, Grenier is a frequent tech investor, the cofounder of startups like a hipster beer company and the sustainability lifestyle media company SHFT.

And as of this past March, Grenier holds the title of "Social Good Advocate" for Dell.

"The most effective way to do well for the planet and people is by creating a business that can scale, so that the good that you do scales," Grenier says.

It's a concept called "social entrepreneurship."

In fact, this past weekend in San Francisco, Grenier was a judge for the final round of a startup competition called The Venture, where "social entrepreneurship" startups (tackling issues like affordable food, water conservation, and climate change) competed for seed money and extra mentorship.

"We recognize that we all have to get together to solve the world's greatest problems," Grenier says. "That means not just paying lip service, but actually handing off the baton to some youngsters, to some people who are entering the market with some new ideas."

This concept of "social entrepreneurship" is important for more established businesses, too, Grenier says: His role at Dell has given him access to billionaire CEO and founder Michael Dell, who recently said something that particularly inspired him.

"You have to recognize this is about my legacy, about our legacy," Grenier recalls Dell telling him. "And we have to recognize that what we put out in the world... we should be responsible for what we put out."

After all, it's literally Dell's name on every piece of discarded hardware and trashed packaging that makes its way to a landfill or a riverbed, and it's important to take responsibility.

But for anybody trying to change the world via a business, "the most important thing" is to set realistic goals, Grenier says.

"In any business, or any social entrepreneurship, you dream big, you look to the sky, but keep your feet on the ground," he says. "Social goals are the same as business goals, you have to scale slowly."

It's just a matter of passion. And with The Venture competition, Grenier says that he's looking at the founders themselves with as much scrutiny as the ideas they're presenting.

"The people who are in the position to succeed are those most likely to take it to the finish line," Grenier says.