He didn’t set out to be an activist.

The chief executive of Dick’s Sporting Goods, Mr. Stack spent his career selling fishing rods, camping gear and athletic equipment at big-box stores around the country.

Dick’s was founded by Mr. Stack’s father in upstate New York. As a young man, Mr. Stack worked for the family business. But he didn’t enjoy the experience. His father was a divisive boss who couldn’t manage a supply chain, and was especially hard on his son.

Hoping to chart his own course, Mr. Stack went to work at a law firm. But when his father fell ill, Mr. Stack came back to help run the company. He soon grew to love the retail business and eventually bought the company from his father in 1984.

Mr. Stack set about expanding across the country, at times moving too aggressively. Overextended, the company flirted with bankruptcy. But Mr. Stack stabilized the business, and in 2002, took Dick’s public. Since then, he has managed to keep the company competitive in the age of Walmart, Amazon and e-commerce

With all of that accomplished and retirement in sight, Mr. Stack wasn’t looking for attention. Then in February 2018, a gunman opened fire at Marjory Stoneman Douglas High School in Parkland, Fla., killing 17 people. As Mr. Stack watched the news, he decided to drastically curtail Dick’s gun sales.

Days after the shooting, Dick’s said that it would immediately stop selling all assault-style rifles, no longer sell high-capacity magazines and require any gun buyer to be at least 21, regardless of local laws.

Dick’s was not alone. Walmart also tightened its gun sales policies after the shooting in Parkland, and companies including Delta Air Lines and MetLife moved to distance themselves from the National Rifle Association.

But for gun rights activists, Mr. Stack’s deeply personal engagement with the issue struck a nerve. The N.R.A. came after Dick’s, and calls for a boycott sprung up on social media.

Mr. Stack was unbowed. He announced that Dick’s would destroy the assault-style rifles and accessories on its shelves instead of returning them to manufacturers.

More than a year and a half after the Parkland shooting, Mr. Stack continues his campaign for stricter gun control, calling on lawmakers to introduce legislation and detailing his journey from businessman to activist in a new book, “It’s How We Play the Game.” He is reportedly exploring a run for president.

This interview, which was condensed and edited for clarity and occurred before any presidential musings, was conducted in New York.

Had you confronted the guns issue before Parkland?

Our journey with guns has been a long one. Around 1999, some kids broke into our store in Rochester, N.Y., and stole a bunch of handguns. A few days later, the cops found these kids, and a couple of them were dead.

I said, “I don’t want to be in this business.” So we stopped selling handguns. We were small at the time, with just six stores, and nobody noticed. We took a little bit of guff from it, but nobody knew who Dick’s Sporting Goods was really at the time.

Who did you take guff from? The National Rifle Association?

No, it was customers asking, “Why aren’t you selling handguns anymore?” Then we opened in Texas and put some handguns back because it just felt that was what the customer wanted. With the assault weapons ban from 1994, we hadn’t been selling assault rifles. But then, probably a year before Sandy Hook, merchants came and said, “To be competitive in the gun business, you got to have assault rifles. This is what’s selling.” So we put them back in.

Then Parkland happened, and you decided to significantly curtail your gun sales.

When Parkland happened — watching those kids, listening to those parents — it had a profound effect on me. It was at that point I said, “I just don’t want to sell these guns, period.”

I’m a pretty stoic guy. But I sat there hearing about the kids who were killed, and I hadn’t cried that much since my mother passed away. We need to do something. This has got to stop.

I came to our management team on that Monday, and started to read a statement I had written. I got emotional, and I couldn’t get through it. Our chief of staff had to actually take the piece of paper from my hand and finish reading it.

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Here is a direct link to the complete interview.

David Gelles writes the Corner Office column and other features for The New York Times’s Sunday Business section, To learn more about him and his work, please click here.