Interesting, significant, and terrible. Parts of the artwork stand out—a copper plate brought back from a student who visited Iran. A picture of his last academic decathlon team in a wooden frame, their initials carved in with the Swiss army knives he bought them. A sketch of him as a Viking with a church burning in the background.

Richard McGowan has collected dozens of pictures during his 25 years teaching. He hangs them up behind his desk, and fills the wall with the colors of student personalities and history. His life before students, though, took place on a U.S. Air Force base in England called RAF Lakenheath. There, his dad worked as teacher at an American Department of defense high school on the base, while his mother organized a federal teacher’s union.

“Growing up in an American school in Europe at the end of the cold war was a weird experience,” he said. “There would be simulated nuclear and biological attacks and the soldiers on the base would be in these big, rubber suits running around with gas masks on and we’d just be high schoolers going out to lunch.”

Although soldiers surrounded him, he still says he had an authentic high school experience.

“There was a football team and letter jackets,” he said. “Our marching band was like 12 kids, and we didn’t have a lit football field, so we played football on Saturday afternoons. We’d play kids from other military bases in England.”

Living in England, he said, made the experience special.

“It was kind of the best of both worlds, because on the Air Force base, it was like a little America,” he said. “There was an American grocery store, and an American hamburger place, but just a short walk from the base was an English village. There, there was a butcher, a baker, a little greens grocer who sold vegetables, and there was a market once a week. It was a simple life.”

Every once in a while, though, real air force missions would disquiet the simplicity.

“When I was a senior, the air force pilots attacked Libya,” he said, “and my best friend Scott’s father was the squadron commander of that mission. A plane had crashed, and a pilot and co-pilot had died, so when Scott came to school that day, I had to ask him, ‘Scott, is your dad okay?’ and he said, ‘Yeah, my dad’s okay. That wasn’t him.’”

His high school experiences, he said, were less hectic than those in middle school.

“My middle school was on a WWII air force base, and our gym was in a giant hangar,” he said. “All the barracks were converted into classrooms, but they were spread out, probably 100 yards away. So we’d leave class, we had 15 minutes between classes, so you know there was lots of chaos.”

Amid the chaos, though, was a true bond with Mr. Jean Hayworth, his eighth grade math teacher. Mr. McGowan spoke at his funeral when he died a few years ago.

“I was terrible in math,” he said, tearing up, “but all the math I learned was in Jean Hayworth’s class. But he was a great guy. It’s funny, because those people, who my parents taught with, I’m closer with than I was with my family.”

He recalled the crazy antics of Mr. Hayworth that inspired how he teaches now.

“One day, I’ll never forget, we were working out of brand new textbooks, and he realized there was a mistake in the textbook,” Mr. McGowan said. “And so, he was like, ‘these textbooks are rubbish. Everybody take them and throw them out the window.’ And we had this long line of windows we always kept open during spring and fall, because the weather was great. So everyone walked over to the window, and actually threw them out the window.”

Two and a half decades later, he’s continued Mr. Hayworth’s legacy.

“Jean had a teaching persona, and I think a lot of good teachers have one,” he said. “I come to school, and I put that persona on in the parking lot, and I’m Mr. McGowan the history teacher 8 hours a day. Good teaching requires you to motivate kids, so there’s definitely a show.”

Knowing how to be a good teacher isn’t new to Mr. McGowan—he prepared to teach from a young age.

“I always knew I was going to be a teacher,” he said. “I still have friends who ask me after 25 years if I’m still a teacher, like it’s some kind of itinerant job I’m going to grow out of. But I think I got another 20 years in me, maybe.”

It’s easy for him because he loves the subject.

“I’m kind of obsessed with the past,” he said. “No, I’m totally obsessed with the past. There’s just a new sense of America of the nostalgia of the past, and I like to pull that curtain back. Because the good old days weren’t actually the good old days.”

He also loves the way his teaching impacts kids the way Mr. Hayworth impacted him. He remembers his favorite students through staying in touch and adding pictures to his ever-growing wall.

“I keep in touch with my favorite kids,” he said. “I had breakfast this summer with one of my all time favorite kids. They were interesting in class, and as they’ve grown into adults, they’re even more interesting. It’s gratifying when the things you’ve taught them in class has helped them in real life, and that affirms I’m doing something worth doing.”