As I was waiting to take the mound at Chase Field one day in early May, I saw a line of kids streaming toward me. They were heading to the field for a pregame ceremony. It was the type of moment which, in the past, would not have registered with me. I'd have been so locked in I wouldn't have even noticed them. Until recently, I had on blinders the days I pitched. I wouldn't hear anyone, wouldn't see anything. I was adamant about doing whatever I needed to do to stay focused on my job that day.

But I'm 44 now, and in a different place in my life. So as the kids got closer, I found myself thinking: You know what? When I was a Little Leaguer, I would've loved to be in this situation. And that freed me to have fun in that moment. I high-fived the Little Leaguers as they passed by.

I'm thinking about stuff like that more now, in my 21st major league season. After coming back from two back surgeries, I've started to try to take it all in. I enjoy the fact that on any given day I can still compete at the big league level. I've always appreciated being out there, but I'm appreciating it a little bit more this time around. Like Phil Jackson, I'm staying in the now.

That's new for me. I never really enjoyed anything I'd done in my career. When you begin to have success, more success is expected of you. I get that; I expect it of myself. People have said, rightly or wrongly, that I've been kind of a prickly guy. But that's part of why I've been so good. I've never given in to anyone.

My father, Bud, was a military man and a police officer. One thing he told me and my brothers and sisters was, "If you have an opportunity to do something, do it the best you can, because you may not get a second opportunity." I took that to heart. Playing for Seattle in 1990, I pitched a no-hitter against Detroit. When I called home, the first thing my father said was, "How come you walked six batters?"

When he passed away, on Christmas Day 1992, I dedicated my career to him. I focused on being the best I could be—not better than others, but the best I could be. That meant having to dig a little deeper when I was tired, being able to throw 130 or 140 pitches, being a warrior. Sure enough, the season after my dad died was my best year to that point, the start of everything. There was always another level to strive for and no reason I couldn't go further.

In the past I've been asked, "Why don't you have more fun?" I never felt as if I had a choice. I had to do well, because I couldn't imagine how I'd feel if I didn't. There were too many people who were counting on me.

These days, though, the fire doesn't rage the way it did seven or eight years ago. Don't get me wrong, I still have the passion and competitiveness to pitch every fifth day. But it doesn't consume me like it used to. Maybe it's because it was a real drag to work my way back from two surgeries. I went into spring training in 2007 still recovering from my first procedure. Evidently, I returned too quickly. After about 10 starts—including a string of four in which I pitched pretty well—I began to get symptoms in my legs. Soon, I found out I had another herniated disk. I'd just finished my rehab, and now I was going to have to do it again, with no guarantee of being able to pitch again. It was pretty deflating.

This season has been good for me, though. It's pretty exciting to be on a Diamondbacks team like this, with a lot of young kids who already have an idea of how to play. It's not like I'm going through a transition period with them in which I'm trying to see what they can do. They already know how to get it done, and that's a lot of fun to be around. If I'm looking for a fountain of youth, well, I just have to look over my shoulder. I'm 20 years older than a lot of these guys. If the energy they bring can't get me going, nothing will.

I guess that's a big reason why I'm finally enjoying myself now. I realize I just as easily could be sitting at home, watching the games on TV. It's much more fun to be a part of it.

Through May, Randy Johnson's 4,672 strikeouts was the second-most in major league history, behind Nolan Ryan's 5,714.