A high school newspaper reporter snagged himself a 45-minute interview with Defense Secretary James “Mad Dog” Mattis after spotting the Pentagon chief’s personal phone number online.

Teddy Fischer, a rising junior at Mercer Island High School in Washington state, was inspired by a profile of Mattis in The New Yorker in May, his journalism teacher, Chris Twombley, told HuffPost. Mattis also is a Washington state native.

Fischer then spotted a May 11 Washington Post article on Facebook. The article included a photo of President Donald Trump’s bodyguard, Keith Schiller, holding papers with a sticky note affixed. Mattis’ cellphone number was written on it. The Post later removed the photo.

Fischer, a staff writer at the school’s The Islander, decided to try the number to inquire about an interview. Mattis didn’t pick up, but Fischer followed up in a text message.

“It was a lark for him originally,” Twombley said. “I don’t think he thought it would go anywhere. But the general called him back on his personal line and left a message for Teddy.”

The school’s journalism team “went to great lengths” to confirm that Mattis was in fact the person who called, Twombley said. After some back and forth with Mattis’ staff, Fischer secured a 15-minute phone interview, which lasted 30 minutes longer than the time slot.

“The angle was more what would the general have to say to teenagers about how to be active and educate themselves in a world that was being defined by terrorism,” Twombley said.

The biggest advice Mattis offered Fischer during the interview was to remain a student of history.

“No matter what you’re going to go into, whether it be business or politics or international relations or domestic politics, I don’t think you can go wrong if you maintain an avid interest in history,” Fischer quoted Mattis as saying. “The reason I say that is you’ll find that really, there’s nothing new under the sun, other than some of the technology we use. I wish now, looking back on it, if I’d known what waited for me in life, I would have put a lot more attention into history.”

Mattis’ boss, President Donald Trump, didn’t come up during the interview, but the defense secretary and the teenager did discuss hot-button foreign policy issues, including instability in the Middle East and how to deal with Iran.

War is “a fundamental and predictable phenomenon,” Mattis told Fischer. “So just mix in all the new technologies, the way a society thinks, and you put all that together, and out of it comes a non-quantifiable that results in victory or defeat.”

Mattis predicted that wars of the future would be fought in outer space and on the internet.

Mattis also told the teenager that the United State shouldn’t move toward isolationism. He echoed Trump’s desire to see NATO members increase contributions to collective defense.

“Being part of a country or an alliance like that is a little bit like going to a bank,” Mattis said. “If you want to take something out, you have to put something in, and I think it’s actually essential.”

Mattis said he called Fischer back because he tries to maintain his connection with students.

“I think we owe it to you young folks to pass on what we learned going down the road so that you can make your own mistakes, not the same ones we made,” he told Fischer.

Fischer’s nerve shows what young journalists should aim for, Twombley said. “The position of the media is always to ask tough questions. A lot of kids his age wouldn’t have done that.”