ATLANTA — Before he was playing in front of 70,807 fans in person and around 111.3 million more at home in Super Bowl LI, De'Vondre Campbell was laughed at in his high school hallway. His team then was a joke.

Before he was declaring himself a voice that would drive the Falcons' redemption, he was knocked out cold with a concussion. He was told it would threaten his football career. 

Before he was raising a daughter of his own, he was a son unsure why his mother was losing her hair.

No Super Bowl-losing team has returned to the championship game since the 1993 Bills. The hangover is real. But this is also a Falcons team that believes it possesses the right personalities to recover from 28-3, to return this season with a vengeance.

And the vengeance begins with a second-year linebacker who slipped through crack after crack after insurmountable crack to get here.

Campbell has the perspective the Falcons will need to get back.

Never mind the fact the Falcons started four rookies on defense in a NFC Championship Game—more than any team in NFL history—and three in the Super Bowl. That's not why they collapsed in Houston. Don't call them young.

Certainly do not call Campbell young.

"That whole 'young' thing—that s--t went out of the window, man," Campbell says. "That didn't matter. It's all about maturity, man. I'm mature beyond my years."

The 24-year-old who's been watching the Super Bowl every week all offseason, story by story, then explains why.

Start in high school.

His team was a punchline. Losing by 20, 30, even 40 points, his 13-sack senior year went unnoticed at Cypress Lake (Fla.) High. He didn't receive a single questionnaire from a Division III school, let alone go on a recruiting trip.

His three head coaches over eight wins in four years never sent highlight tapes to anyone, never sent him to a camp. It's nearly impossible to get lost in the recruiting shuffle, especially in Florida, but Campbell was.

All he could do was chase, and chase, and chase the quarterback some more as his team was embarrassed weekly.

"I can't find it in my heart to give up," he says. "I don't care what the score is or what the situation is."

And in what should've been his final football game ever—the John Carrigan All-Star Classic—Campbell dominated. He had a pick-six called back. He was relentless, all night, and nearly was the game's MVP.

Afterward, a stranger approached Campbell and handed him a business card.

It was a coach from faraway Hutchinson (Kan.) Community College.

Oh, Campbell believed in himself. He once raced local legend Sammy Watkins stride for stride in the 200 meters at counties, in track, and didn't care that the stopwatches indicated he lost—Campbell is still convinced he won.

"To the day I die," he says, "I'll say I beat him."

Now, holding this card, that flicker of belief grew. Campbell had no clue what a "Hutch Blue Dragon" was but didn't care. He'd take a chance on himself. He took his screaming motor off the edge to Kansas, and then that motor nearly ruined his career before it began.

In August camp, the 200-pound Campbell turned the corner at warp speed, ducked and smacked head-first into a 300-pound pulling guard.

He blacked out. He remembered nothing.

When he woke up in the trainer's room 20 minutes later, he asked, "What the hell just happened?" He was forced to stay in his dark bedroom for three weeks. If he needed to step outside during the day, he wore sunglasses. His vision was blurry; his head throbbed; a simple conversation with friends triggered a piercing ringing in his skull; then he'd forget the conversation completely five minutes later.

"Noise, like us talking, that'd bother me," he says. "Anything bothered me. The first week was baaaaad."

When Campbell laid down to get sleep, it was nearly impossible.

"When I was laying flat on my back," he says, "it felt like my head was just...my brain was just...I don't know. It was f--ked up. When people say they have concussions—severe ones—I know what a severe one feels like.

"If we were having a conversation, I'd be like, 'What were we just talking about?'"

Campbell rewatched the play on film and still couldn't remember a thing.

He missed weeks of classes, the entire season and absolutely hated living in this virtual Siberia. Which all begs the question: Why stay? Why even risk his brain at this point? There was no guarantee he'd even make Hutch's team next season after redshirting this season. Only 12 out-of-state players did each fall. His reason was simple.

Quitting meant returning to Fort Myers.

Quitting meant cruising down Dr. Martin Luther King Jr. Blvd. and falling into drugs or jail or worse.

"A lot of my friends were in jail," Campbell says. "Back then I had the mindset that I was not getting a regular job. It was just not happening. If football didn't work out, there was only one other option."

And that's drug dealing.

"Yeah," he admits. "I was not getting a job."

So Campbell stayed, and the concussion, he believes, turned out to be the best thing for him. Campbell lit it up at Hutch and then had three years of eligibility at the University of Minnesota instead of two. That third year is what propelled him into the NFL as the 115th pick in 2016.

Unfortunately, also during that third year, Campbell's mother, Cathryn, suffered a second heart attack. Or was it her third? He's not sure. The horror of the first one was enough. If the Campbells hadn't lived five minutes from the hospital in Florida, she might've died. She woke up in the middle of the night, unable to breathe.

After this heart attack, Campbell told Mom to stay home for senior night.  

Then, there's the breast cancer. This is what still gives him chills because De'Vondre knows he could lose his mom "at any point." When he was 11, all he knew was that Cathryn was losing her hair and in the hospital. Dad concealed the dark reality that she could've died. And when doctors thought they had removed all of the cancer with one procedure, they were wrong.

A second procedure was needed.

She's still alive.

Campbell wants to bring her back to another Super Bowl.

"That's why I approach every situation like I do," Campbell says, "because if she can go through near-death situations and still come out with a smile, there's nothing I can go through that can be worse."

So by the time Chuck Smith met Campbell, Campbell was ready. He was tough and athletic but—above all—a leader. Smith, a former All-Pro defensive end, has become a sack-whisperer of sorts, training defensive linemen and linebackers for the NFL combine. Campbell, naturally, took charge of his group that included the likes of Reggie Ragland, D.J. Reader, Yannick Ngakoue and Noah Spence.

He acted twice his age. Smith saw "an old man's soul" who'd be ready to start from day one in the NFL.

Smith was a JUCO player himself. He could relate to the edge Campbell brought to every workout. So the former Falcons end told 10 teams—including friends with the Bengals and Giants—about this hidden gem, this linebacker who should go no later than the second round.

Atlanta's Dan Quinn was the one who acted on the advice.

"What's very important: Do you have that dog in you?" Smith says. "Every pass-rusher who's great had it. Reggie White had it. Bruce Smith had it. The linebackers. J.J. Watt has it. Von Miller has it. They want to win so bad, they're willing to do whatever it takes to learn to be the best and figure it out because they want to be the best.

"De'Vondre has that dog in him."

Now, Smith believes Campbell is a Pro Bowler. In time, he sees more.

"The sky's the limit," he says. "He's lightning-fast. Tall. Rangy. You know who one day I hope he becomes? Cornelius Bennett. I'm hoping in the next four to five years, he's Cornelius Bennett. If the middle 'backer got hurt, Cornelius had to step in. And Bruce and those guys couldn't rush, Cornelius one year played defensive end. He can play in a 4-3, a 3-4 and defensive end. I'm hoping De'Vondre develops into Cornelius Bennett.

"I hope his skill set gets to Cornelius Bennett. He has that skill set."

Campbell repeats that he plans on leading in 2017 and beyond. If the Falcons defense, his defense, starts letting a lead slip away again, he'll be the one who speaks up, who blitzes spontaneously, who reverses the momentum back in Atlanta's favor.

After everything he's been through, he's ready.

"They're going to see a whole different person this year," Campbell says. "Believe me. A whole different story."

He's already seeing the field differently. Campbell had LASIK eye surgery over the offseason and picked off a pass in his first exhibition game.

And he believes his story is the Falcons' story. So many teams spew cliches this time of year. Slogans are slapped on T-shirts and ignored.

Atlanta's "brotherhood" mantra, he insists, is real. It stuck last year and will stick this year because Campbell knows how fortunate he is to be here. If that one coach didn't see him, if he decided to go home to Fort Myers after the concussion, if he did anything differently at all, he has no clue what would've happened.

"We have something that's pretty special," Campbell says. "We actually care about each other. I've had teammates who told me that when they were on other teams, they hated coming to work. They absolutely hated it. And we have these same guys saying, 'I love to come to work. I look at you guys like brothers.' That's something we implemented in our organization: a brotherhood. Something bigger than ourselves."

So Campbell will make a point to talk to the unit's star, Vic Beasley, more this season.

Most people can't relate to Beasley, he admits, because he's so "different."

"He's the type of person I feel like I could sit down and have a full conversation with," Campbell says, "and he would be one of the most interesting people you've ever talked to. I've never done it. I would love to."

In 2017 and beyond, he'll do this at every opportunity. He'll accentuate the best out of everyone around him.

And he'll keep this team's eyes looking forward.

"We can't get last year back," Campbell says. "It was a good run. But we have all the pieces in line to make another run. We just have to do it. And this time we have to finish the job.

"That's the most important thing: finishing."

Tyler Dunne covers the NFL for Bleacher Report. Follow him on Twitter: @TyDunne.