Harper was just 19 a year ago when he played in his first one. He hadn't known what to expect, but like pretty much everything else, he never seemed overwhelmed.
"Last year, it was being able to see Chipper [Jones] in his last [All-Star Game]," Harper said. "That was something I was excited for, and I was pretty much in his back pocket that whole time."
This time around, Harper knew that the enduring memory would be the chance to see the greatest closer of all time throw his last pitch in an All-Star Game. Harper stood and cheered in the bottom of the eighth inning when Mariano Rivera trotted in from right field. He may be young, but he gets the meaning of this kind of baseball moment.
"I'm so excited and very humbled and blessed to be here," Harper said. "I'm going to take it all in and try to have some fun."
Harper started in center field for the NL, batted ninth and was hitless in two at-bats. He smoked a liner off Chris Sale to Miguel Cabrera at third in his first at-bat in the third inning and popped to short in his second, against Grant Balfour, in the sixth inning.
"I was trying to lay off [Sale's] slider," Harper said. "I knew I couldn't hit it. I was trying to lay off that, get something straight. I got something straight, I put some good wood on it. It felt good."
Harper switched to right field when Andrew McCutchen entered the game in the fourth inning. When asked about playing center, he said he'd joked with Nats manager Davey Johnson, a member of the NL coaching staff, about it.
"It felt good out there, it felt comfortable," Harper said. "Being able to play alongside Carlos Gonzalez and [Carlos] Beltran was a lot of fun. Being able to play behind [Matt] Harvey was a blast, also."
Harper had a unique experience by having his dad pitch to him in the Chevrolet Home Run Derby on Monday, and his family stuck around for the All-Star Game and got to experience a little of what Harper experienced.
"That's something I'm going to cherish for the rest of my life," Harper said. "I really just try to enjoy it the best I can and try to do my best on and off the field. I don't really care about accolades and things like that."
Harper's teammate, pitcher Jordan Zimmermann, got the All-Star treatment as well. He made the club, dressed in the locker beside Harper and was introduced as a member of the team. But Zimmermann was unable to pitch because of a stiff neck.
"It's awesome," Zimmermann said. "I wish I could pitch, but it's better to take a little rest right now. It's great to be around these guys. It's fun to watch."
Zimmermann said an All-Star Game might have been a bit more special because it came in his fifth Major League season.
"It's being around the names that are this locker room," he said. "It's a special thing to walk in and see all these guys. It's the first time it kind of sunk in."
Along the way, Zimmermann paused to reflect on his journey.
"Growing up, I never threw hard," he said. "I had to work for everything. It's finally paying off. If you'd asked me three years ago if I would be here, I'd have to tell you no. But it's a great honor, and I don't take it for granted."