The Skyy boxing gym outside Tuscaloosa is hard to spot from the end of the dirt road, tucked into the rear of the nondescript aluminum-sided building on a quiet offshoot of Route 30 not far from the banks of Black Warrior river. There’s little outward indication the two converted units in the rear are the training headquarters of one of the world’s most accomplished prizefighters, but there’s no mistaking the sense of occasion when Deontay Wilder peels up in a customized Lamborghini Aventador with a faux gator-skin wrap, an audacious choice in any context but positively extraterrestrial against west Alabama’s modest backdrop.

It’s two days after Thanksgiving and this normally bustling college town is mostly deserted, the University of Alabama student body having decamped either home for the holiday or to Auburn for the annual Iron Bowl grudge match that divides communities, friendships and families across this football-mad state. But the champ is here. There was a time when Wilder would have been one of his country’s most famous sportsmen, which makes the 32-year-old among the biggest casualties of boxing’s gradual retreat toward the margins of American life. At one time the heavyweight championship of the world was the most prestigious and coveted title in all of sports, but the fight game’s lack of central authority has wrought four major sanctioning bodies that have served to create confusion among casual observers while cheapening the currency of a championship.

Wilder holds the WBC’s version of the long-fractured heavyweight title and has for nearly three years, while Britain’s Anthony Joshua owns the IBF and WBA belts. These days, a fighter needs a special something to cross over into the cultural mainstream in America, whether it’s a hyperkinetic, made-for-YouTube style (like Manny Pacquiao) or a built-in fanbase (like Oscar De La Hoya). There’s no reason Wilder, a charismatic knockout machine in a chiseled 6ft 7in, 220lb package who is undefeated in 39 professional fights with 38 wins inside the distance, can’t fit that bill. And there’s every reason to believe a much-fancied unification fight with Joshua next year will serve as his launchpad to crossover stardom.

The pair have been on a collision course for years and their eventual meeting could end with the unification of a heavyweight championship that’s been divided since Lennox Lewis retired more than a decade and a half ago – and the sorely needed clarity it would mean for boxing’s bellwether division.

Wilder splits time in Atlanta with his fiancee and four children, with a fifth due next year. But Tuscaloosa, the state’s fifth-largest city whose name almost rings onomatopoeic for southern, will always be home. He still owns a house in town and the memories come forth in torrents as he speaks fondly of his formative years as a multi-sport standout for nearby Central high school, getting in the occasional schoolyard scrap and goofing off with his team-mates on bus rides to away games and harboring dreams of playing basketball or football for the University of Alabama. After graduating he followed those ambitions to Shelton State community college, where he worked on his grades to gain eligibility and eyed a transfer for a chance to play for the hometown Crimson Tide.

That all changed with a routine visit to the doctor’s office in 2005, when he learned his unborn daughter with his then girlfriend would be born with spina bifida, an incurable birth defect in which there is an incomplete closing of a fetus’s developing backbone and membranes around the spinal cord, leaving it exposed. Right then Wilder, only 19, knew he needed money and he needed it immediately.

“We could have terminated the pregnancy,” he recalls quietly in an easy Alabama drawl. “We could have just left this whole thing alone. Let everybody go about their business, but I felt like it was the right thing to do. I felt like my daughter deserved to live, no matter what the conditions were, no matter how old I was. No matter what I don’t have, I was going to make a way.”

He pauses.

“If I don’t make any right decisions no more in my life, I can say at least I done it one time.”

Wilder considers the prenatal diagnosis a blessing, since it gave the young couple a window of time to prepare for Naieya’s arrival and the requirements for a child with special needs. The most pressing concerns were financial, which prompted Wilder to pick up a series of jobs: waiting tables at IHOP and Red Lobster and driving a truck for Budweiser. It was never the most fulfilling work, though Wilder never batted an eye: “I will never let my pride get in front of nothing I do. I’m not going to let my family suffer because of my pride.”

But it was the gnawing memories of his athletic prowess that led him through the Skyy doors on 19 October 2006: three days before his 21st birthday. There the gangly youngster was initially rebuffed by gym owner Jay Deas, but his persistence and raw ability soon won over the trainer and their partnership has since flourished.

He is not the first decorated boxer to take up the gloves at an advanced age – Rocky Marciano, Earnie Shavers and Sergio Martínez all started after 20 – but fighters who succeed at the highest level after starting so late are rare. His debut also came so far into the Olympic cycle that he, a total fistic novice, found himself taking aim at the Beijing Games within months of his first visit to the gym.

“I didn’t know anything about the Olympics,” he admits. “My whole mentality was to walk in this gym and turn pro. I was going to be a journeyman. I needed money for my daughter like now. One thing we knew is that if we kept winning, that we couldn’t be denied. I’m three months in the gym talking about the Olympics. Miracles happen.”

Facebook Twitter Pinterest Wilder poses with daughter Naieya in 2007. Photograph: Robert Sutton/AP

He surveys the modest gym, festooned with posters and memorabilia from throughout a career with no shortage of doubters, not least because Tuscaloosa is hardly a boxing hotbed. “A lot of people don’t understand, up in here is where it really hurts, where you really got to get it,” he says, gesturing toward the ring in the corner. “This is where all your decision-making comes from. The mental game. Do you really want to do this or do you not? And if you don’t, then go home.”

Wilder’s crash course of an amateur career – a scant 35 fights in total which included upset wins at the national Golden Gloves and US championships – ended in Beijing with a bronze medal and he signed with a promoter immediately after. Another busted misconception soon followed with the paltry $5,000 check he earned for his professional debut: “I felt like every guy made a lot of money that stepped in the ring. I didn’t know there was levels to get to the big prize, the big money. But I knew what I was going to do whatever it took to get to that point.”

Learning a lifetime trade in a few short years was not without challenges, but Wilder’s unique cocktail of work ethic, innate athleticism and boundless confidence kept him on course and he’s not lost a bout since: “I love fighting, I’ve been doing it for a while, even when I was young. It might not have been boxing, but I polished the street-wise mentality of fighting and turned it into an organized thing. It’s like basketball, you play street ball then you join a school team and it becomes organized. Same way as fighting. You start in the streets somewhere: protecting yourself, not being a bully. All fighters have a story of coming up from a rough spot. Most of your best fighters fight their way out of poverty. That’s just the way it works.”

All the while he kept his job with Budweiser, a job he loved due to the camaraderie, physical activity and, not insignificantly, the health insurance: “I’m lifting, I’m pulling, I’m tugging. All day long. You’ve got 1,200 cases on your truck. Seventeen-hour shifts and going to the gym afterward.”

If I was every other ethnicity, any type of person that’s not a black man, it would be different Deontay Wilder

Since graduating to the paying ranks Wilder has been brought along with extreme care. Too carefully, some critics have alleged, but few can quibble with the results. He’s won each 39 of his fights, all but one by stoppage, frequently in spectacular fashion. He fulfilled his promise to Naieya, who after a battery of surgeries remains catheterized but gets around without crutches and lives an otherwise normal life, when he captured the vacant WBC heavyweight title with a win over Bermane Stiverne in January 2015, becoming the first American heavyweight title-holder since Shannon Briggs eight years prior. He’s since made six successful defenses and now finds himself within touching distance of a unification bout with Joshua that would elevate his profile, and that of his beleaguered sport, to levels untold stateside since Mike Tyson’s heyday.

But even more than fortune Wilder is intrigued by the unique cultural heft a unified heavyweight championship would bring. He counts himself as a deep admirer of Colin Kaepernick, the former San Francisco 49ers quarterback whose protest of the national anthem has thrust issues of social injustice into the spotlight even as it cost him his career. “That was a big sacrifice,” he says. “He may have regrets because of the heartaches and pains that he’s done been through, but he put himself in the position and he’s going have to stick through it.

“He’s one of the woke black people, he’s not brainwashed. That’s what I like about him. It’s only going to get stronger from here. He took a stand, he did the things that some would be scared to do, say the things that some wouldn’t dare to say because they were afraid of losing their jobs. I support him. Why stand for something that’s not for you or talks about killing your ancestors? Who would stand for something like that? How many people stand at home?”

“Once you obtain power in the heavyweight division, especially as the heavyweight champion, you can check the president and people will feel it. It’s a different platform because we don’t have a commissioner, we don’t have nobody. We’re our own boss. If [Kaepernick] was the champion of the world, then it would be easy. His career could still go on. That’s why if you can do this, this sport at the top level, especially reaching stardom, the sky’s the limit.”

When we meet at the gym it’s been three weeks since Wilder’s one-round destruction of Stiverne in a rematch before a charitably announced crowd of 10,294 at Brooklyn’s Barclays Center – and four since Joshua stopped the stubborn Carlos Takam before an estimated crowd of 78,000 at Cardiff’s Principality Stadium, smashing the world attendance record for an indoor boxing event previously held by Muhammad Ali. While both rivals have similar résumés, Joshua is a household name at home and one of Britain’s most celebrated athletes while Wilder, for all his success and promise, remains familiar only to hardcore boxing fans. It’s clearly a sticking point for the American, who becomes more animated when discussing the factors undercutting the sport’s domestic visibility.

“The problem with America is we got media downing American fighters, we got analysts and so-called experts downing American fighters, you got former champions that have made their mark in the sport but don’t want to see their legacy passed down to American fighters.

Facebook Twitter Pinterest Wilder needed less than one round to knock out Bermane Stiverne in their November fight. Photograph: Al Bello/Getty Images

“I never understand that, especially as a champion. You should want somebody to come and pass you. You should want someone to keep the sport alive and build it up. Even the champions don’t want their legacy passed because they don’t want to be forgotten, but if you did it right the first time you’ll never be forgotten. Casual fans come into boxing and listen to the so-called experts downing our fighters but praise the foreigners. We adopt the foreigners but down our own. That’s a huge problem. In other countries, they praise their fighters.

“A lot of people don’t want to pull the race card but let’s be real: I’m a realist, I’m a woke realist, I’m not brainwashed at all. I see what’s going on. If I was any other ethnicity, any type of person that’s not a black man, it would be different. If I was any other color but black, it would be different.”

He cites the mania surrounding former middleweight champion Kelly Pavlik as a testament to America’s enduring obsession with great white hopes. When I mention that Tyson’s comically lopsided first comeback fight with Peter McNeeley is to this day the second-highest grossing heavyweight promotion in history, his eyes widen and he lets out a guttural laugh.

“It’s just the time we live in,” he says. “Black people have always been strong people. We’ve been doing it for years and years and we’re going to continue to do it. We’ve always had to be people to fight out of situations and it’s made us strong along the way.”

Inevitably, the discussion turns to the big fight. Wilder says he’s only crossed paths with Joshua once before when he was in London as a member of Sky Sports’ broadcasting team for the Briton’s heavyweight title defense against Wladimir Klitschko at Wembley Stadium this year. Their interaction was brief and one of mutual respect, Wilder says, but the opportunity to finally size up Joshua in person did nothing to dent the Alabaman’s supreme confidence.

“I think he respects me a hell of a lot,” he says. “Same here. But when it comes to boxing, I know I’m the best. I know it. They know it. It’s just matter of time. They can say what they want in public, they can try to stall and make people believe certain things. But people are getting tired. They’re getting restless. They’re not trying to hear all this stuff. Don’t make excuses, make the fight happen.”

Joshua’s promoter, Eddie Hearn of Matchroom Boxing, has suggested Wilder should first fight British contender Dillian Whyte, reportedly offering a $3m purse plus the US television rights to the American with a handshake deal to fight Joshua next, but Wilder wants it in writing: “They’re stuck on this Dillian Whyte because Dillian Whyte gave Joshua somewhat of a time. They want to compare, use Dillian as a measuring stick. That’s an easy fight. Of course that’s an easy fight.

“At the same time we’re not going to be looking like we’re chasing. When you’re talking about the best fighting the best, champion fighting champion, it shouldn’t be like a circus. Let’s make this fight happen, no matter what the terms are. It ain’t like I ain’t done nothing. I’m the longest reigning [heavyweight] champion in the game, so put some respek on the name.

“But they know I’m a risk. They don’t want to risk their gravy train. They can make money off turds not doing nothing. What does that tell you? You’re really just running it as a business. You ain’t no champion. In that case give up the belt and you can still do that. Give me the belts. Or fight.”

Wilder was taken aback by the intoxicating atmosphere of Wembley on the night and confesses to imagining himself fighting on that stage. He also learned a thing or two about Joshua, who came off the floor and survived a series of thorny moments to score an 11th-round stoppage that sent Klitschko into retirement.

“One thing we did learn about him is he overcame adversity that night,” he says. “We seen him get knocked down and get back up. We see him go through the fatigue, very tired, and somehow gain a second breath. No matter what Klitschko did or didn’t do, it happened. Being able to get back up through a hard time and finish the job.

“Some guys get fearful of big crowds but I love it. The more the better for me. When I’m in the ring I don’t hear them or see them. It’s more quiet inside the ring no matter how many people are in the stadium. You get that tunnel vision.”

Wilder is in talks for a March fight with Luis Ortiz in Brooklyn with Joshua reportedly close to announcing a date with Joseph Parker, who holds the WBO’s version of the title. Should both make it through unscathed, it would set the stage for the unification of all four major belts: “One face, one champion, one name. That’s what the heavyweight division needs.”

It’s an outcome that might have seemed impossible when Wilder first walked through the Skyy doors just over a decade ago, but after the improbable journey that’s followed only a fool would write him off.

“When I was five, six years old, there was a poster that my mother gave me with a bear he was running a race and he was about to cross the line,” he says. “And it said you don’t know what you can do until you try. It stuck with me, always to this day and probably till I die: You don’t know what you can do until you try.”

