The person behind one of the country’s fastest-growing animal rescues can’t even vote yet. And neither can most of the people leading its 10 chapters across the nation.

Lou Wegner, a 16-year-old actor and singer, started Kids Against Animal Cruelty when he was 14. The organization, which uses social networking to encourage adoptions at high-kill animal shelters, has helped 20,000 pets escape euthanasia in two years.

Lou, an Ohio native, said he became aware of euthanasia at shelters when he went to Los Angeles to make the short film Be Good to Eddie Lee. The director suggested that he volunteer at an animal shelter.

“It was heartbreaking,” he says. “All these dogs crying in their cages. Knowing they would be put down broke my heart.”

The group started with Lou and his friends, carrying signs on street corners, and a Facebook page with 47 friends. Now it has more than 12,000 U.S. members and 50,000 members, supporters and partner coalitions across the globe, he says. Its website is kidsagainstanimalcruelty.org.

The group gets a boost whenever Lou hits the red carpet or the airwaves. He had a small role in Clint Eastwood’s Trouble With the Curve, just finished a pilot called The Thundermans for Nickelodeon, and co-hosts a weekly Global Voice Broadcasting radio show called Love That Dog Hollywood! Kids & Animals.

With that kind of exposure, the group’s goal has become global – getting people to adopt from shelters, to spay and neuter pets, and educating them about pet responsibility, Lou says. He advocates a no-kill policy, and hopes adults will join in because “they know so much more than we do.”

KAAC chapters around the country are run by teens, including a pair of sisters in New York City who worked to find lost animals and get pet food to beleaguered owners after Superstorm Sandy.

Lou hopes to have a chapter in every state eventually, “because the bigger the group you work with, the bigger difference you can make.”