Former Washington Redskin offensive lineman Tre Johnson leads a discussion during the diversity class he teaches to freshmen at Landon. (John McDonnell/THE WASHINGTON POST)

It’s not only Mondays that the boys in Mr. Johnson’s ninth-grade Modern World History class want to talk football. Life in the NFL’s trenches is a topic of endless curiosity.

Could Mr. Johnson have blocked Ray Lewis, they love to ask.

What about Hannibal, who taught the ancient Romans the meaning of fear?

Genghis Khan?

“One time I asked if he could take on the whole Trojan army!” 15-year-old Michael Soraci says.

Tre Johnson takes a three-mile walk around the track at Landon during his lunch hour, part of his efforts to lose weight. (John McDonnell/THE WASHINGTON POST)

The answer is always the same.

“There’s nobody on the planet I couldn’t block!” Mr. Johnson brays. “All-pro or not, I’m gonna put him on his pockets!”

But five minutes of football chatter is all Tre Johnson indulges before getting down to business. The lesson on a recent school morning: an introduction to Islam and the Crusades.

Johnson sports a far less menacing look — khakis, shirt, tie and sweater — than he brandished as a Washington Redskins guard from 1994 to 2000 and again in 2002, reaching the Pro Bowl in 1999.

Back when his first step was more explosive, roughly 13 years and 60 pounds ago, his job was protecting quarterback Brad Johnson and blasting running lanes for Stephen Davis. Today, at 41, it’s expanding the minds of 14- and 15-year-old freshmen at Landon School, prodding their thinking on matters of world history and cultural diversity in classrooms he strives to make intellectually challenging and emotionally safe.

“Since Day One, Mr. Johnson has been encouraging us to express our opinion,” says Josh Hunter, 15, a student in two of his classes. “I feel I can say what I think, and I really love that about him. I don’t feel judged. There’s a certain trust in his classes that makes you want to speak. Some teachers don’t rub off on you the same way.”

‘Never let football define me’

Set on a 75-acre oasis in the heart of Bethesda, Landon is a privileged cocoon where upper-school tuition is $32,000, class size averages 16, a code of conduct stresses respect and honesty and all 680 boys must play a sport. But football isn’t why Johnson, who holds bachelor’s and master’s degrees from Temple, was hired to teach history nine years ago.

A father of five, he’s more engrossed in his 11-year-old daughter’s lacrosse games and 6-year-old son’s wrestling, martial arts and lacrosse practices than NFL games, which he watches only sparingly.

“If you can’t play anymore, it’s almost like torture,” Johnson says. “You think, ‘I used to be able to do that.’ You know when your era is over, and you can’t compare yourself. But I would love to block for RGIII! Let me block for Cam [Newton]. Let me block for LeSean McCoy. I would love to have had that opportunity because I respect them as athletes and people and ballplayers.”

Johnson, who retired in 2003 after eight seasons with the Redskins and one with the Cleveland Browns, misses the all-out brawls of game day. He misses the camaraderie with linemates Jon Jansen, Cory Raymer, Keith Sims and Andy Heck. And he misses the fat NFL paychecks.

But he’s not living in the past. He never had much use for fame and doesn’t make his NFL pedigree his calling card today.

“I promised my mother I would never let football define me,” said Johnson, who earned his two degrees before entering the 1994 NFL draft. “You can’t be a fool and think, ‘I’m going to play football forever.’ Every moment you play football is luck. You know it’s a gift. You have to know it’s going to end.”

The hallways of Landon’s Upper School are lined with lockers, with backpacks strewn on the floor on either side, making the passage even narrower. When the bell chimes to signal a change of classes, it’s as congested as Interstate 95. But to walk behind the massive Mr. Johnson is to know why Davis, the Redskins’ all-pro running back, loved rumbling through the gaping holes in his wake.

Like all of Johnson’s classes, the morning’s Modern World History lesson follows a structured format, and the boys pop open their laptops and notebooks to record the salient points. It begins with a review of the reading assignment, with Johnson coaxing information from his charges Socratic-style.

“When did Western civilization start?”

“Who were the Sumerians? What were their major contributions?”

“What did Egypt introduce to the world?”

As hands shoot up and students blurt out the answers, the point becomes clear: The Western world didn’t dawn with the Greeks and Romans but owes a debt — for written communication, city planning, irrigation, government and bureaucracy — to cultures many history books ignore.

Johnson gives a quiz every other class to make sure students keep up with the material. And he reveals the subject in advance to help them prepare. “I’m not trying to trick them,” he explains. “I’m on their side. I want them to win.”

As this session winds down, he suggests the boys prepare to identify three similarities among Islam, Judaism and Christianity the next time they meet. 

“Be able to answer this if I were to ask it,” he says. “And it can’t be something as general as, ‘They’re all religions!’ And remember your topic sentence. Make sure you have a thesis. And have it relate to the topic sentence. And come in rippin’ and rockin’ and ready!”

‘Lucky to be drafted here’

Lunchtime at Landon is a caloric feast tailored to teenage boys’ metabolism: giant tubs of peanut butter, fajitas with mounds of guacamole and an amply stocked table of cold cuts and cheeses for constructing skyscraper-scale sandwiches.

Johnson avoids the temptation and makes a protein shake in the history department’s office, then heads to the track, where he walks three miles, twice daily, in an effort to shed the weight he piled on after quitting football. Three years into the routine, he’s finally under 400 pounds again, with a goal of reaching his high school playing weight of 275 by age 50 while tackling the diabetes, high cholesterol and elevated blood pressure he’s saddled with.

A third-generation professional athlete (his father played for the Nets in the American Basketball Association; one grandfather boxed; the other played in baseball’s Negro leagues), Johnson was a track star at New York’s Peekskill High who excelled at the shot put, javelin, discus and hammer. Remarkably quick, his combination of upper-body strength, speed and size made him a formidable left tackle in college, charged with protecting the quarterback’s blind side.

Projected as a first-round NFL draft pick as a junior, he was hurt by staying a fourth year at Temple, where the team won just three games his last two seasons. The Redskins scooped him up early in the second round, 31st overall, after taking quarterback Heath Shuler in the first round.

A 300-plus pound lineman, Johnson was converted to guard and tasked with sophisticated blocking schemes, often “pulling” to the opposite side of the field to confound defenders.

Controlling his weight was a constant struggle. So was the pursuit of a winning record.

In seven seasons under Coach Norv Turner and a return stint under Steve Spurrier in 2002, Johnson was part of just three winning seasons in Washington and one postseason, in 1999, when he, Davis and Brad Johnson earned Pro Bowl honors.

Coached by former Hog Russ Grimm, the Redskins’ line anchored an offense that ranked second in total points and yards that season. It was an eclectic bunch bound by trust. Raymer, a Wisconsin woodsman at heart, rolled up to games at FedEx Field in an RV with a roasted pig strapped to its roof. Jansen, Raymer’s flannel-clad hunting buddy, was an introverted genius at right tackle. Sims was the by-the-book NFL Players Association representative; Heck, a dutiful family man. And Tre Johnson was the tattooed enforcer who attacked every snap as if it were a New York street fight.

“The five of us, we wouldn’t let anything happen to each other, and we wouldn’t let anything happen to our quarterback,” Tre Johnson said. “We were different, but we were cohesive.”

But for the most part, the Redskins of Johnson’s era fell short of their potential. And it’s the losses, more than the wins, that have stayed with him.

“I feel bad because D.C. is a great fan city, and I was lucky to be drafted here,” he said. “We had enough talent to win, but we weren’t disciplined. We had a lot of party boys. We had a lot of dudes with big egos who would buck coaches.”

The physical toll has stayed with him, too.

Johnson can’t sleep more than three hours at a stretch. There’s not a morning he doesn’t wake up in pain, and it takes a full hour to get moving in tolerable discomfort. Though he never had a concussion diagnosed (such diagnoses were uncommon even a decade ago, when players who “got their bell rung” staggered to the sideline for a whiff of smelling salts and gulp of oxygen, then went back in), he can’t tolerate bright lights or fluorescent light of any kind. That’s why he keeps his Landon classrooms dim, lecturing amid the natural light that filters through the windows.

Looking back, Johnson realizes he didn’t have to spill so much of his guts on the field. Grimm told him at the time that he could accomplish all the blocking necessary to hold his man up with smart hand placement. Nineteen surgeries later (seven on his shoulders, seven on his knees, an elbow, hands and Achilles’ tendon), Johnson concedes he was overly aggressive at his own expense.

“I was trying to make war, and it was foolish,” he says. “I could have been a lot better and played longer had I adhered more to the cerebral elements of it. But I wanted to make noise! I wanted to make an impact!”

‘Utter confidence in him’

Today, Johnson is making a gentler impact at Landon, a once homogeneous school where minorities account for 33 percent of the enrollment, as the driving force behind a new diversity class designed to help students understand and respect people of different backgrounds and ethnicities.

“We pull kids from everywhere in the city, and there is a need for dialogue,” explains Ehren Federiwicz, head of the Upper School, who tapped Johnson to develop and teach the mandatory freshman course. “We have utter confidence in him. He can get into these issues and do it in a safe way. Ninth grade is the perfect age because they are forming a sense of self.”

On this day, Johnson’s freshmen are learning about affirmative action.

“We’re going to talk about one, Abigail Fisher, who has a legitimate beef,” Johnson said. “She took her case to the Supreme Court. And this could affect you.”

Johnson then sets the stage for a 16-minute PBS news program about Fisher, a teen who was denied admission to the University of Texas while others with lower grades were accepted in order to ensure a more diverse student body.

At the conclusion, Johnson said, “So what I want to ask you: Who thinks affirmative action should stay in place? Is it a good thing or a bad thing? You tell me.”

Four hands inch up. Then five.

“They can do a little of it,” one boy says.

“They should just take the smartest kids,” says another. “I don’t think it’s fair.”

After everyone weighs in, Johnson asks who is the best lacrosse player in the group.

They point to a classmate, Brian, who manages to both beam and blush.

“Okay,” Johnson continues, “so say I want to go to Princeton, Duke, U-Va. or Johns Hopkins. I have better grades, but they accept Brian because he rocks the lacrosse stick. Is this fair?”

Class adjourns without a tidy answer.

“He’s a tough teacher, but he gives us good information,” Ian Napolean, 14, said. “He doesn’t just give us the facts. He teaches us very thoroughly, and he’s not just talking all the time. He conducts the discussions, and he wants us to learn from it.”

Johnson’s own education continues as well. He plans to start work this fall on a doctorate of educational leadership, juggling schoolwork with teaching, with a goal of becoming a school administrator.

“There are a lot of 6-2, 300-plus-pound guys in the world,” Johnson notes. “What makes one person an NFL guy and another guy a bouncer in the front of a club? It’s work ethic. Doing the little things. Not only training when you have to train, but working on your technique, getting in the weight room, performing on game day. It’s the mentality you have to have.

“And I’m trying to make an imprint on these students about accountability and responsibility as it relates to their job in the classroom. You’ve got to be willing to do the little things, and whatever it takes, to be successful to get to that next level.”