Recently acquired Yankees lefty J.A. Happ discusses his mental approach and what it is like now being on the New York stage with Post columnist Steve Serby.

Q: You used to beat yourself up between starts. Did you ever consult a sports psychologist, or how did that change?

A: I think it’s just something I had to learn how to be better at over time if I wanted to stay in the big leagues and succeed. I knew it wasn’t a healthy habit. And then I also think having kids — 2015 my son [J.J.] was born, ’17 my daughter [Bella] — I think having them to go home to, getting married as well, having people to go home to, to kind of rely on and turn the page and shut it off, ’cause they don’t care, and they don’t even know whether I did good or bad, right? So I’m just Dad. So that’s kind of a healthy balance for me.

Q: How much of a nightmare was that beating yourself up the way you did?

A: It was stressful, I think, for me. The mental part took its toll in that way. I always prided myself on being mentally strong, like preparing for starts properly, and pushing myself and being strong out there, but the part about getting over a bad outing or some bad results, I wasn’t always great at.

Q: Sleepless nights?

A: A lot of ’em.

Q: The worst … the most you beat yourself up.

A: 2011 I had a really tough season. I got sent down for a couple of weeks. So that was kind of a wake-up [call]: “Hey, you’re gonna have to change some things.” You know, you go down, and there’s no guarantee you’re gonna come back up.

Q: But you never tried a sports psychologist or anything?

A: No. I mean, I read the Mental ABCs of Baseball and talked to other players and coaches and managers, but not necessarily at the time any sports psychologists.

Q: Who gave you the best advice how to conquer this hindrance?

A: I really think the addition of my wife [Morgan] over the last several years, meeting her and getting to know her, she’s helped me the most. She’s a former athlete herself, she played basketball. She’s very positive, that’s the biggest thing. Again, that wasn’t a strength of mine, I wasn’t able to kind of turn the page and look at the positive. I was stuck in kind of the rut of looking at the results and the negativity of that. And she’s helped me kind of overcome that.

Q: How would you describe your mound mentality?

A: I try to be as focused as I can and aggressive. I think for me, the walks, when I look back, those are the things that get me in trouble, put free guys on base. When I’m aggressive in the strike zone, that’s when I’m usually at my best.

Q: What was it like getting struck in the head with the Blue Jays by a Desmond Jennings line drive in 2013?

A: At the time I really didn’t know what happened. It was a scary situation. I think fortunate for me, I had a little fracture behind my ear, but I actually tweaked my knee kind of falling after I was hit, and that was the most difficult part, was the rehab of that. My head was better. I think when I came back, instead of focusing on the ball coming back at me, I was worried about how my knee felt, so it was sort of a blessing in disguise.

Q: You were carried off on a stretcher.

A: I could have probably got up. They told me to be still since it was a head injury. I was coherent and everything.

Q: That’s something you can’t allow yourself to ever think about on the mound.

A: Fortunately, I was able to kind of get over that. I’ve had several balls back at me, several of ’em hit me, you just hope that’s one of those freak things that we sort of take that risk. It can be a scary thing, but you kind of try to put it out of your mind.

Q: What drives you?

A: I feel like I’ve had a good inner drive for a while, especially since I got into pro ball. It was such a thing where, OK now we’re playing the best players in the country from high school and college, how do I stand out? So my work ethic’s gotta be better. So that’s kind of where I feel like it took off, college and then getting drafted. If anybody ever asked me what I wanted to be when I grew up, I told ’em professional athlete. So I didn’t really specify — I loved basketball, I loved baseball, so I was hoping to be one of those two.

Q: Describe the big, bright New York stage.

A: I like it. I feel like this is as good a stage as there is in sports to play.

Q: If you could test your skills against one hitter in baseball history, who would it be?

A: Mickey Mantle, I think. … Growing up what I heard from my dad and grandfather just what an amazing player, and how fast, speed, power, like the whole combination.

Q: Who is one pitcher in baseball history whose brain you’d love to pick?

A: A lot is made of veteran players trying to help teach younger players, and the one guy for me who did that to the greatest level and most extreme in a positive way was Jamie Moyer. So I don’t know who I would pick, but I know that my experience with someone like that to pick somebody’s brain who’s been doing it a long time, that was my favorite kind of experience from an older player. He would come to me and he would ask kind of how I’m feeling in certain situations, what I’m thinking. He was proactive in that more than I think most everybody else is as far as helping the younger guys.

Q: What do you hope Yankees fans will say about you?

A: You know, I think sometimes people might take my lack of emotion … I don’t know what they take it for — but one thing I hope that they understand and I know my teammates will realize this as we keep going here is that I’m giving everything I got when I’m out there. I don’t show a lot of emotion, but a lot of that’s intentional. I’m trying to stay focused on the task at hand. But when I go out there, I’m giving you everything I got, and I feel like that is the most important thing, the way to gain the respect in the clubhouse and in the dugout.

Q: Are you having the kind of major league career that you might have imagined as a kid?

A: Yeah, you never really know, so you get drafted and your goal is to make it to the big leagues and stick in the big leagues, and everybody says the hardest thing to do is stick here. It’s my 10th season, so I’m certainly proud of that. And I’m very proud of especially the last few years.

Q: Why do you think you’ve been able to stick?

A: I think it’s learning yourself a little bit. I think I had a period there where I was maybe trying to be a type of pitcher that I wasn’t naturally inclined to be. I think I kind of accepted who I am as a pitcher, and I think that’s definitely helped me.

Q: What do you mean?

A: I grew up watching — you take like a Tom Glavine for example, a left-hander who pitched forever, it was an amazing career and this guy’s got four pitches and he’s locating everything perfectly. Certainly that’s always the goal, the aspiration, but I’m not necessarily that guy, you know what I mean? I’m coming at you, I’m being aggressive, and I’m trying to throw every pitch 25 percent [of the time], right? I’m trying to throw 25, 25, 25, 25. Maybe that’s not a strength of mine to do that. So I gotta learn what’s good for me, what I’m good at, and the hitters will show me. So I finally trusted that. And I think it’s helped me a lot.

Q: What was it like winning the 2008 World Series with the Phillies, in five games over the Rays.

A: It was incredible, it really was. I was on the playoff roster, and was able to be along for that. What an awesome group, and that’s still a highlight of my baseball career.

Q: What do you remember about the 2009 World Series, when your Phillies lost to the Yankees in six games?

A: I think Jay-Z was out here doing a concert, or singing their song, with Alicia Keys — which is like the first song I actually listened to when I got traded, I was like getting pumped up. It was like that welcome-to-New York song [“Empire State of Mind”]. I just remember it was crazy, it was awesome. I was in the bullpen for the World Series, and still being so loud in there. So fortunate to go to two. Everybody was telling me that, all the veterans, like, “You gotta embrace this, people play their whole career and don’t even make one playoff game, you’re in two World Series” … and now, 10 years later, realize how true that is.

Q: How long do you want to continue with your career?

A: I don’t ever want to put a cap on it as long as I feel good. I think one thing I would love to do is play long enough for my son to remember, so he’s almost 3 so that’s got to be several more years. If I’m still getting some good results, then I’m gonna keep going.

Q: He will turn 3 in October.

A: He’s full of energy. Really happy kid. And he’s changed my life in so many great ways. He’s just so fun to be around.

Q: Describe manager Aaron Boone.

A: Had this little virus I had [hand, foot and mouth disease] and he was calling every day to check in. I’m very impressed with all the staff and the guys here so far, it really seems like, which I’ve heard before I came here, but a first-class organization.

Q: Pitching coach Larry Rothschild.

A: His son was able to come meet me when I was stuck here. We played catch in Central Park for a couple of days to keep my arm going when I wasn’t with the team, so that was a fun thing.

Q: How imposing was it facing Aaron Judge and Giancarlo Stanton?

A: They’re tough. Obviously the size, and then the ball comes off their bat differently than most guys in baseball. Those guys are unique to the game in that way. Plus their talent. It’s formidable as they come really.

Q: You don’t have to face them anymore.

A: (Chuckle) That’s a nice thing. It’s a great thing!

Q: Describe the recent All-Star game, when you pitched the 10th inning and got the save in an 8-6 AL win.

A: That as well. It was pretty emotional, I was so happy to actually find a way to get in that game as well. Just awesome to be in the same clubhouse with the best players on the planet. I loved All-Star Games growing up as a kid, and like just crazy to walk in that clubhouse and be amongst that group. It’s really fun.

Q: Describe your major league debut in 2007 against the Mets at Citizens Bank Park.

A: Well, it didn’t go as planned. I think I gave up three runs without getting an out to start. But I managed to get into the fifth inning and gave up a couple of more and was out of there. But it was an awesome experience. They talk about baseball being The Show, that was The Show right there.

Q: Boyhood idol?

A: Ryne Sandberg.

Q: What NBA players did you like growing up?

A: My dad was a Larry Bird fan playing for the Celtics, so I was a Larry Bird fan growing up, and then even more so in my teenage years, Michael Jordan.

Q: Describe your mother’s meatballs.

A: (Laugh) It’s an old recipe she found somewhere, or I’m not sure if it’s from my grandma or where it’s from. If I’m home for any amount of time she’ll always make them for me and it’s one of my favorites.

Q: Three dinner guests?

A: Ulysses S. Grant, Elon Musk, my father.

Q: Why Grant?

A: I’m so interested in the times, 1860s, I just want to hear more specifics and kind of learn a little strategy.

Q: Musk?

A: I think he’s obviously sort of like a pioneer of the future in a sense, so I just think he’d be an interesting guy to just kind of say, “Teach me something,” and let him go off for the dinner and just listen.

Q: Did you play catch with your dad growing up?

A: He took me out in the backyard, he set up a little mound and he was crouching down with his catcher’s mitt and I was wearing his knees out and throwing it all over the place, and he’d never complain, just kept getting it, throwing it back, and that’s a huge reason why I’m here right now.

Q: Favorite movie?

A: “Shawshank Redemption.”

Q: Favorite actor?

A: Matt Damon.

Q: Favorite singer/entertainer?

A: Eric Church.

Q: Favorite meal?

A: A good steak.

Q: Is there a New York Yankees Way?

A: I feel like I can kind of pick up in it a little bit just talking to some of the guys. I think there’s a professionalism involved in it. I can already sense it.

Q: Do you feel this team can win a World Series?

A: Oh, there’s no doubt. I look at the personnel in the clubhouse, and it’s awesome to see. So I think day in and day out, I think we have the capability of going on one heckuva run.