A quick Q&A with a not-your-everyday runner.

Sean Astin rose to fame as the lovable Mikey in “The Goonies” before joining the fellowship of “The Lord of the Rings” and the much-anticipated “Ninja Turtles.” The busy actor, director and producer talks about racing, cross training and how he wants everyone to run for a cause with #Run3rd.

PHOTOS: Behind The Scenes With Sean Astin

When did you first start running?

When I was 13 years old, my best friend lived across the street from me and his dad ran 10Ks. He invited to me to join a race with him and I jumped on it. At that point, I hadn’t run one straight mile in my life, but I was a kid and in good shape. We started and finished at the LA Coliseum, where people were cheering for all the runners—I felt like an Olympic star. From that moment on, I was locked in. I joined my high school cross country team after that—it was amazing.

Do you train with a coach or prefer running on your own?

I mostly do my own thing. I read running books, consult online running resources and am always talking to other runners. Sometimes I’ve done the exact opposite of what you’re supposed to do, but it’s a trial and error. I had a trainer when I ran my first marathon and now I owe him a lot for teaching me how to wrap my head around running. When I’m not running, I like riding my road bike and doing the Insanity workouts.

What races do you have coming up?

I’m running the 50th annual JFK 50 Miler on Nov. 17 in Maryland and the 20th Anniversary Walt Disney World Marathon on Jan. 13 in Florida. I’ve run the LA Marathon three times, a handful of half marathons, like the Tinker Bell Half Marathon, hundreds of 10Ks and am just starting to get into 5Ks.

Sounds like you’re a big fan of Disney. What is it about their races that keeps you coming back?

I grew up at Disneyland. I’ve done a lot of work for Disney and my daughters live, sleep and breathe the characters. The place does something to people. When people are there, they know it’s about being positive. Disney has done a fantastic job of activating the running community and finding a great formula for promoting healthy choices and values for their audience. I’m happy to be a part of it.

Tell us about #RUN3RD.

It’s a sentiment that encourages runners to make a dedication to a loved one, a cause they believe in or an idea that they like. We’re encouraging everyone on Twitter to take a moment and make a dedication by tagging #Run3rd. That can carry over to runners writing #Run3rd on their race bibs, shoes, arms, etc. It’s just a hash tag like the millions of others, but I am infusing it with sustained passion and intention. The longer it goes on, the more I reflect about why it is able to grow. The saying goes, “I run first for myself, I run second for my family and I #Run3rd for that dedication.”

This profile first appeared in the September 2012 issue of Competitor magazine.