HANSCOM AIR FORCE BASE, Mass. - Standing at the front of a classroom filled with roughly two-dozen eighth-grade students, a man in his late twenties with Kennedy-esque features teaches a lesson on how to form an argumentative essay using Harper Lee's novel "To Kill a Mockingbird."
"When explaining a quote, you need to first ensure you know what it fully means," said Gregory Kessler, an English language arts teacher at the Horace Mann Middle School in Franklin, Massachusetts. "You need to show how it supports your claim."
As his class looked on intently, Kessler continued to explain how to use evidence from the text to prove a claim.
"This could be a sentence or two putting a quote in your own words," said Kessler. "It is an easy way to start off your explanation. It gets you thinking more deeply about the quote itself."
A lesson on writing a well-developed essay is typical in most middle schools. The man teaching it, on the other hand, is anything but standard-issue. In addition to working in his community as an educator, Kessler is a first lieutenant in the Massachusetts Army National Guard.
Kessler's military and civilian career have grown side-by-side. After graduating from Athol High School in Athol, Mass., Kessler accepted an Army ROTC scholarship.
"I saw it as a great way to help out my community and pay for college," he said.
During his second year of undergraduate studies, Kessler realized he wanted to become an educator.
"When I was a sophomore in college I substitute taught and really enjoyed it," Kessler said.
After graduating from the University of Massachusetts Amherst in 2011, Kessler commissioned as a transportation officer in the Army National Guard and simultaneously began his teaching career.
Leading his troops and leading his classroom have parallels, said Kessler.
"I try to instill in the kids and the Soldiers that without clear communication there is a lot of misunderstood realities in this world," said Kessler.
Kessler believes the training and experience he has garnered from his time in the Army has been instrumental in his success as an educator.
"The Army has taught me a lot about being an instructor and being able to lead others," he said. "You treat Soldiers a lot differently than you would treat students, obviously. But you try to use a lot of the same things. I try to bring a lot of energy. I think Soldiers and students both respond to enthusiasm."
That energy comes across very clearly when Kessler starts lecturing about literature in the classroom.
"What makes him an excellent English teacher is [that] he loves books," said Mary Cotillo, assistant principal at Horace Mann Middle School. "He gets really passionate about them and he discusses them with that passion."
That affection for literature started for Kessler at a young age.
"The stories of heroism and strength always intrigued me as a kid," he said. "I always liked finding characters to emulate and look up to."
Now, as a teacher, he encourages his pupils to do the same.
"It is important that students relate to the novels they read," Kessler said. "Many of the themes and ideas they are reading about happen in their own lives."
Having a teacher invested in helping adolescents foster an interest in reading is critical, said Cotillo, but equally important is the personality of that person.
"Our boys in particular really connect with [Kessler], said Cotillo. "Here he's a football coach, he's a baseball coach, he's a military guy – all of these things that our boys aspire to be. It's really important to have a role model that will embrace that kind of passion around literature. It makes them feel that it is OK. You're not going to be a geek if you like to read. It doesn't make you any less popular, any less macho and any less tough if you enjoy good books."
It's that connection he has fostered that often makes it difficult for Kessler and his students when he has to leave for duty.
Kessler's unit was called to assist in recovery efforts in Texas, Florida and Puerto Rico in the aftermath of Hurricanes Harvey, Irma and Maria.
"First and foremost, our concern is for him and making sure he knows that whatever obligation he has [with the Army], he needs to fulfill it," said Cotillo. "It is always hard for us to miss him. We can always get a substitute, but it's never the same. It's never as good."
"It's been difficult," admits Kessler. "You have to always have lesson plans ready to go in case something comes up, like a natural disaster or some type of training."
But even with the best constructed substitute plans, there is just something missing when Kessler has to go away.
"The kids know him, they have a relationship with him, and they miss him when he's not there," said Cotillo. "No matter who you are, you could be the world's best English teacher, but if you go in there and try to teach the kids a new skill they are always going to want to know what Mr. Kessler wants them to do."
Despite the sometimes difficult situations that come with being a Citizen-Soldier, Kessler said he does not intend to give up his military career anytime soon.
"I love teaching and being an active member of the Guard, he said. "I want to continue to do both and serve my community."
Cotillo hopes that in the future more service members will decide to become teachers and help educate the next generation of Americans by bringing with them their unique skills and experiences.
"If anybody can handle being a middle school teacher, it's a Soldier."