On a day when he already donated $100,000 to charity, Pete Alonso also cashed in for the Mets — fittingly with a home run.

Both of Alonso’s grandfathers served in the military. On his mom’s side, a marine, and on his dad’s side, an intelligence agent in the army.

So the decision to give a portion of his $1 million earnings for winning the Home Run Derby was an easy one, considering Alonso knew exactly the causes he wanted to support.

Alonso presented two separate donations of $50,000 to the Stephen Siller Tunnel to Towers Foundation and the Wounded Warrior Project. The organizations work to support first responders and other servicemen and women.

“For me, I just feel fortunate every single day with the opportunity I have. I just feel extremely blessed, that’s one of the reasons why I wanted to donate,” Alonso said during press conference to make the donations official before the Mets beat the Pirates 6-3 at Citi Field on Friday night. “I feel really strongly about people who put their lives on the line every single day. For me, I think that’s kind of overlooked every once in a while. It’s something that we all take for granted.

“The price of freedom isn’t free. You’ve got guys overseas paying that price every single day, so I mean that’s why we’re here right now.”

Alonso made the Pirates pay on the field in the bottom of the sixth when he hit his 34th homer of the season to put the Mets up 5-3. The solo shot brings the first baseman just eight home runs away from surpassing the single-season franchise record of 41.

The Mets rookie discussed how a bad day at work for him is nothing compared to what first responders deal with on a day-to-day basis. He stressed how important it was to show his gratitude and appreciation for those who put their lives on the line every day.

It also, Alonso said, was about contributing to New York City, which he feels has taken him under its wing during his first season with the Mets. He said he feels connected to the city and appreciative of what it’s done for him, supplying his passion to give back a whole new meaning.

“I am blessed and this is just an opportunity to give back. I don’t want to be known as just a baseball player,” Alonso said. “Some people see me on the field as a competitor, just a spirited guy, but this is the more emotional side of me. I just want to help, that’s all.“I just want to be good person, too, I don’t want to just be a good baseball player. At the end of the day, it’s all about helping people.”