Transcript for Patrick Dempsey on Life After 'Grey's Anatomy,' Still Being 'McDreamy'
You know, biking in the woods of Maine with Patrick Dempsey is something most "Grey's anatomy" fans can only picture in their wildest Mac dreams are if you live in his hometown or a lucky "Nightline" correspondent -- not me -- you may get to do just that. Here's ABC's Neal Karlinsky. Reporter: We're about as far as Hollywood as you can get in Patrick Dempsey's tiny hometown of lewiston, Maine. The actor best known as mcdreamy from "Gray's anatomy" hasn't been on the hit show for a year. Can we take a picture? Yes, you can be on "Nightline," say hello to "Nightline." Reporter: It makes walking around with the 50-year-old trying to find out what his next act might be surprisingly challenging. Somebody wants to say hello. She's looking at you here. Hello. You won't interrupt, it's okay. I remember you juggling in the front yard. For me, I was younger, it was great. We were all younger back then. It was great to see your success in life. Thank you very much. I've been very proud of you. Reporter: Turns out juggling helped the pre-mcdreamy version of Dempsey make it out of this old mill town of 36,000 people. That after his first dream fell through. He'd hoped to become an olympic downhill skier. I left Maine when I was about 17. And I was going to run away with the circus. I auditioned for this play, "Torch song trilogy." You were actually going to run away. I was too young, they wouldn't let me in at ringling brothers. Reporter: We spent three days watching him decompress, learning about his Dempsey center to help people battling cancer, a cause very personal to him. He lost his mother Amanda, seen here in this footage from ten years ago. That's where Patrick lives when he comes in the summer. Reporter: To ovarian cancer in 2014. Your mother I know fought for a long time before she lost her own battle with cancer. It seemed like it came back every two years. It was slow-growing. We had her a lot longer than the doctors sort of predicted. Reporter: I spent the weekend with him riding race bikes, a passion we both share as part of his huge Dempsey challenge fund-raiser. Make a right-hand turn up here. This is the first one. I'll let you be incognito. Reporter: Dempsey comes here after a whirlwind year. No hands. It's cold! Reporter: The dramatic and sudden end of his ten-year run on "Grey's anatomy" sparked questions about why his character was killed off. A split with his wife of 17 years and talk of divorce. They're back together now. A new movie "Bridget Jones' baby." Enough tabloid headlines to get under anyone's skin. "Grey's anatomy" was a remarkable ride. Without that success I probably wouldn't be here today talking to you. Are you happy with the way it ended? Well, you know, I think everybody was sort of surprised how abrupt it was. Was Shonda rhimes done with you? I think it was time for us both to be finished. That's diplomatic. Well, you know, it was -- it's hard to keep the creative energy going for ten years. There was a lot written that you'd become a diva on set. Right. I can understand why people would say that. It's interesting. I think you can never really judge an actor on set. Because depending on the dynamic of the scene, you are asked to plug into an emotion. Reporter: Then there's this surprising fact about the controversial end of his character. I haven't seen the final episode. You haven't? Never saw the final episode, didn't watch it. Do you want me to tell you what happened? I think it doesn't end well. One door closes, another door opens, my old man used to say. This is jack. Reporter: The next door was "Bridget Jones' baby," alongside Renney zelling were and Colin firth. It's all new to you. Reporter: Playing the familiar role of that irresistible guy. I knew I had to do something. Everybody's like, he's done, career finished, retiring, he's not acting anymore. That wasn't at all the case, I love acting. Reporter: He says things are good at home again with his wife and three kids. How are you doing with your wife? Great, really good. It's a lot of work. You can't not work on it. It's good to say, okay, what's my issue, what's yours, and how do we work on that? Is it true you're looking to have another baby? This is the funny thing about what you get into magazines and they put these quotes out. Then it gets picked up online. Then all of a sudden you're having another baby. What you're saying is you're having two more? We're having triplets. I just want to announce that tonight. Reporter: For the record, no more babies. But it took coffee and pastrieds at his favorite local spot -- Good to see you again. You too. Reporter: To find out his first nickname. And a clue that all this admiration, a steady stream of women we never saw ease up, didn't always come so easy. What'd they call you growing up here? Nothing I want to repeat. Come on. I had nicknames. Like? Nothing that began with MC? I was a small guy, I was "The amoeba." Not your Normal nickname. I was a late bloomer. I was too. Yeah. Reporter: After pastries comes bikes. And the eighth annual Dempsey challenge. A huge weekend bike ride and fund-raiser for his Dempsey center. Are you blown away the way this has grown? Absolutely. Beyond question. It's just remarkable the turnout. But it also speaks to how profound this disease is and how it affects everybody. Look at this. Reporter: The route is filled with supporters on and off the bike. Thank you very much. Nice to meet you. Thanks for being here. Reporter: Less interested in Hollywood than a local boy done good who put his hometown on the map by helping care for those affected by cancer. Thanks F S fs for representing us. My pleasure. Proud of you. Thank you. Reporter: The fact that he has fun doing it doesn't hurt either. This is mile 200 of the Dempsey challenge. It's okay, I'm okay, I can make it. Whoo! Reporter: He finished his ride to great cheers. More than $1 million raised. As for his career, that ride has taken a new path and Dempsey says he's ready. You've got that rom-com thing down. Do you ever shake your head, I want to play a serial killer now? Of course you do. About what I do next. Are you tired of being mcdreamy? I don't think I'll ever get tired of that, it'sing there about be to the rest of my life, I have to accept that. The question is will I be known as anything other than that later in life? That's the question. Reporter: For "Nightline" I'm Lewis karlinksy in lewiston, Maine.
This transcript has been automatically generated and may not be 100% accurate.