When not dropping in off 14-foot vertical ramps, Andy Macdonald’s side hustle involves earning pocket money as a consultant for skateboarding companies looking to crack the youth market. He is ideally suited to the role.

If ever you were to find yourself needing to know what someone like his 13-year-old British teammate, Tommy Calvert, might look for in a new skateboarding product, Macdonald is the man in the know.

“I skate with these kids every day,” says Macdonald. “I talk like them and I wear their clothes. I’m just like Tommy. “I just …” he pauses before chuckling upon realising how best to explain the key difference between him and Calvert. “I just have grey hair.”

Last summer, Macdonald, a legend of the sport who once skated through the White House on a trip to meet the then president, Bill Clinton, turned 50. This summer, he hopes to make his Olympic debut in Paris the week he is 51.

If things go to plan, he will be joined there in the park competition – one of two skateboarding disciplines contested at the Olympics – by Calvert. This would mean a veteran father of three competing for Team GB alongside a boy not even old enough to attend high school in his adopted home of California.

No national skateboarding squad has featured a wider age range than the 37 years that separate Calvert and Macdonald. In a sport predisposed to appeal to a young demographic, Calvert pushes the lower end of a traditional age limit that Macdonald exceeds by a number of decades; generations merging in the least conventional of Olympic sports.

It is close to two years since the pair first met at a skateboarding training facility in San Diego that has subsequently become something of a second home for them both on their Parisian pursuit.

Born in Liverpool to two English parents, Calvert has been based on the US west coast since the family moved for work reasons when he was three. Although a dual citizen, there was never any question which nation he would aspire to represent. “We’re from England,” his father, Paul, says.

Macdonald’s route to the British team took longer to materialise. Despite being a founding member of the USA Skateboarding governing body, after watching some of his peers compete for other countries on the sport’s Olympic debut in Tokyo, he realised he could get a British passport through his Luton-born father.

“It hadn’t even occurred to me beforehand to go down that route,” he says, pronouncing the final word in his native American accent, omitting the effect of the “e”.

Macdonald is a name known to all within the sport. A former competitive partner of Tony Hawk, skateboarding’s biggest breakout star, he holds the record for the number of vert medals won at the X Games – long considered the sport’s pinnacle competition.

But with vert skateboarding not an Olympic discipline, he was afforded no special privileges when looking to join the British setup, and was even required to submit the same video as every other potential recruit to prove he was capable of completing certain tricks.

So when Calvert’s innocence encountered Macdonald’s unrivalled experience at the sport’s primary elite training centre that just happened to be located in the state they both lived in, they were united by a common goal: to qualify for the British team. A few months later they achieved that ambition at the British championships, held in the slightly less glamorous environs of Hemel Hempstead, Hertfordshire.

For Macdonald, it meant some tricky marital discussions. A professional skater since 1994, he had been “winding down” in recent years, primarily competing in masters events and no longer making enough money to live off the sport. So when he and his wife together decided he would target an Olympic dream that had not been a possibility for most of his career, it was under the proviso that it would not come at the expense of their savings. Involvement with the British team meant funding was assured.

Calvert’s desire for a professional skateboarding career led to his dropping out of traditional education in favour of home-schooling, which better fitted around his daily training schedule and travel commitments to global competitions.

Although there was no skateboarding heritage in his family, he had first picked up a board aged seven and improved so rapidly that he was travelling overseas to compete within four years. By that point, his list of sponsors was already extensive. “The day I got my first board I skated all the way home, and then to school and back every day,” he says. “It was instant love.”

Britain’s two skateboarding representatives at the Tokyo Olympics – Sky Brown and Bombette Martin – were aged 12 and 15 respectively, with Brown claiming bronze to become GB’s youngest ever Olympic medalist. Fuelled by their success, Calvert – who turns 14 just before Paris – is adamant that “age is just a number”, insisting “you can do anything at any age”. It is a mantra truer in skateboarding than almost any other sport, and Calvert’s impressive maturity evident in conversation is aided by the time he spends in the company of older skateboarders. “I don’t get treated like a young kid,” he says. “I feel like I’m a lot older in my head.”

Conversely, two of Macdonald’s three children are older than a peer he regularly trains alongside. Now in his sixth decade, he says he cannot imagine a time when he will no longer jump on his skateboard: “I would just melt. Skateboarding is part of who I am and it’s what I’ve always done.”

Yet there are some realities even the most youthful outlook cannot avoid. Macdonald tells a story of competing at an Olympic qualifier in Argentina last year when he finished the competition and realised his ankle was bleeding after taking a knock from the board. The next morning it was black and swollen and he could barely move it.

“I watch kids fall and hurt themselves, and think if I took that slam I’d be out for a week,” he says. “It just takes way longer to heal, the older you get. The physical side of it is a constant reminder: ‘Yeah, you’re old.’

“Maybe behind my back everyone goes: ‘That’s the crazy guy who won’t give it up.’ But there’s a slew of skateboarders who won’t give it up. We call them Rad Dads. I’m definitely a Rad Dad.”

Whether his unlikely French foray proves fruitful will be determined in the coming months. The top 44 in the world rankings will compete at a newly created Olympic Qualifier Series across May and June for one of 20 male park skateboarding spots available in Paris. Aided by quotas imposed on competitors from each country (which rules out a vast number of the highly ranked Americans and Brazilians), Calvert and Macdonald are both firmly in the mix.

Should he fall short, Macdonald is long enough in the tooth not to be disheartened by an event that is vastly different from the one in which his legacy is assured. “I made my living as a vert skater and that discipline isn’t part of the Olympics,” he says. “Hopefully it will be in the future. And if Team GB are looking for 60-year-old vert skaters … well, never say never.”