Andrew McCarthy left home at age 17, a departure that marked the end of his relationship with his father. As the "brat pack" actor's oldest child reached young adulthood, he feared they would drift apart, too.

To prevent that, he made a pitch to his son, Sam, then 19. He suggested they walk the 500-mile Camino de Santiago, the famed pilgrim's trail in Spain. McCarthy had his own transformative experience on the Camino a quarter-century ago, one that helped him find himself. He sensed that Sam would find meaning in the trek, too.

Now 21, Sam is an actor in his own right, recently playing Christina Applegate's son on the Netflix series "Dead to Me."

McCarthy's career started with '80s movies like "Pretty in Pink" and "St. Elmo's Fire." Over the decades, it has morphed into television directing and travel writing. He pulls from these storytelling skills in his new poignant and often funny travel memoir, "Walking With Sam."

In an interview that's been edited for length and clarity, McCarthy talked with the Star Tribune about self-discovery, parenting and the wisdom of keeping your mouth shut.

Q: On a practical matter: You didn't have time to get in shape for this. No conditioning?
A: When Sam said he'd go, I went on the computer, bought two tickets, and two days later we were in Spain. We were in OK shape, I guess. But you can walk yourself into shape. People make the mistake of over-conditioning, over-preparing, carrying too much stuff. You don't need to bring anything, just two pairs of shorts, two T-shirts, a change of underwear and off you go. It's an absolute life-changer. I say it's the best thing I ever did twice.

Q: You already had a good relationship with Sam. Why was it so important to you to take this trip?
A: We were close. But I didn't want what happened with me and my dad to happen with me and Sam. I had no template, but I wanted to rewrite the way we dealt with each other. On the trail, I was parenting but I was acting differently. I didn't have to fix. All I did was listen, and then I could say, "In my experience, I do this." That allowed him to come to himself and come to me. I offer my take, which allows him to take it or leave it, which allows him to have space, which allows him to come to me. It's a shift — it's subtle, but profound.

A: How the heck did you master the art of keeping your mouth shut?
Q: Most of the time you're not gonna go wrong if keep your mouth shut! I don't know if I've mastered it, but the more you do it you see how effective it is. You get the results you want.

I also started to see he's a very different guy from me. We think our kids are knockoff versions of ourselves — they look like us and sound like us — but to see him every day over five weeks, and I mean really see him. We all want to be seen. It takes a long time for kids to see their parents as real people, too, with our foibles, anxieties, fears and insecurities. It's a sign of respect to him to let him in, and he's engaged more happily in a relationship with me.

Q: You write about how he was very frank with you about experimenting with weed and acid. How did that hit you?
A: Talk about keeping your mouth shut. I have a history of alcohol and drug abuse that's not any secret. I took care of it 30 years ago, but it was a big part of my youth and derailed my life. The only solace you can take is talking about it. My kids have heard me talk till I'm blue in the face. But no one has ever stayed sober from information, particularly a parent's information. He doesn't show signs of being out of control the way I was. But you want to protect them, and it's terrifying.

Q: You've written before about the quest to find oneself in the face of challenge. Was this mostly a physical challenge?
A: This walk is a lot of things. The Camino reveals you to yourself, whether you like it or not. You may intend to have one kind of experience, but you may get something else. There's the physical exhaustion, mental challenge and the spiritual connection you get from pure walking, the repetition of it. The act of pilgrimage is about dedication. There's no external discovery. For centuries and centuries, people have walked this trail. There's no new land to discover. It's all internal, about your relationship to and discovery of the self, which is very private. On this trip there was also a his, mine and our experience.

Q: How did the experiences differ?
A: With Sam, you sit my son down for a chat and you don't get very far, but get him moving, and it comes out. For me, I'm a travel writer. Travel has been the university of my life. Taking yourself out of your comfort, learning about yourself — there's the Emerson quote that it's about the journey, not the destination. But this trip was a lot about the physicality of the experience. It allows you to confront yourself, to burn off layers that protect the self.

I faced an insecurity that my son will wake up one day and hate me and our relationship will be over — however misplaced, it felt genuine. And reacting from a place of fear is never good. The Camino reveals. Then you deal with it. In this instance, in walking with Sam, behaviors in our relationship came to the fore and we could address them in real time.

Q: Did documenting it on social media change the way you experienced the walk this time?A: That's so interesting. I haven't been much of a social media person. I've hired publicists to keep my privacy! So this is 180 degrees opposite and a slightly uncomfortable fit. But the first day I posted, people responded so much, and it was suddenly like they were on the journey with us. I enjoyed that aspect. Plus it helped me recall or sum up each day, like journaling.

Q: What will we learn overall from this book about fathers and sons, or parents and children and how to stay connected?
A: For me, it's about parents and kids and parenting, about me trying to figure out how to parent my son. We're always reconciling ourselves to our own parents and then copping to all we do and don't do as parents ourselves. I discovered a sense of over-responsibility I didn't know I had. Watching Sam's evolution, and then when he decided to go beyond me on the walk, to a farther end point — that metaphor was too much to resist. Having our children succeed beyond us is our greatest desire.

Q: Are you going to have to do this with your other two children, who are younger?
A: My 16-year-old said, "Can we just go to Paris?" But my little guy wants to go and I'm game. I have another in me.