In 1984, Nike was in trouble. Growth had stalled, profits were down and a misjudged move into clothing left it with piles of unsold inventory. Rivals had beaten it to new crazes for aerobics and leisure shoes. Sales fell. “Orwell was right,” Phil Knight, who was chairman and chief executive, began his annual letter to shareholders. “1984 was a tough year.”

But Air, a new film set in that same year, opens this week, and shows how Nike went on to become the world’s No 1 shoe and sports brand, a company whose revenue topped £37bn in 2022.

It’s directed by and stars Ben Affleck as Knight in all his shell-suit and mirrored shades-wearing, purple Porsche-driving 80s pomp. Air also stars Matt Damon as Sonny Vaccaro, a Nike sports marketing executive in desperate need of a hit. But the real star of this story is the Air Jordan shoe.

Air tells how, against everyone’s advice, Vaccaro signed a sponsorship deal with the rookie basketball player Michael Jordan, luring him away from more viable rivals Adidas and Converse, by presenting him with his own sneaker – the Air Jordan. Even more controversially, at the behest of Jordan’s formidable mother, Deloris (played in the film by Viola Davis), he gave Jordan points on every pair sold, kicking off a revolution in the way sport and its stars were marketed around the world.

Nike officially released the Air Jordan 1 sneakers to the public on 1 April 1985 at the price of $64.95. It expected to sell 100,000 pairs in the first year. Instead, backed by clever marketing that suggested the NBA had banned the shoes for being too colourful (it hadn’t), it shipped 1.5 million in the first six weeks.

You’d have done well to hang on to a pair. Today, unworn Jordan 1s sell for north of $20,000 (£16,000) on the resale site StockX. The Air Jordan brand sits at the heart of today’s multibillion-pound trainer collecting boom.

Jordan has been called the biggest pop culture hero in American history – someone who transcended not just his sport but race, class and generations. His rise from humble beginnings – a North Carolina boy who didn’t make the grade for his high-school team, the son of a bank employee mother, and a General Electric plant supervisor father, later murdered – made him the embodiment of the American Dream.

Last but very much not least, he was an astonishing athlete – as is obvious even to people with no interest in sport, much less US basketball.

Though Jordan retired for the third and final time in 2003, Nike has continued to introduce new models under his name each year. Today there are 37 Air Jordan styles available, not including countless colourways, collaborations, limited editions and retro Jordans.

In 2020, Netflix broadcast The Last Dance, the 10-part documentary that followed Jordan’s career in compelling detail. Coinciding with twin ramifications of lockdown – a captive audience, and a hunger for comfier clothes – it drew a global audience of 24 million and turbo-boosted interest in its star.

Last year, the Jordan brand made Nike $5.1bn, up 70% from 2020. Based on that figure, its namesake would have pulled in $256.1m from a decades-old licensing deal without lifting a finger, let alone a basketball – more than double the amount from his entire NBA career. Forbes estimates his net worth at $2bn.

It’s not only Nike and Michael Jordan who have benefited – the Air Jordan shoe has changed the market for both vintage and resale trainers and helped cement them as collectibles on a par with the art world.

“The Last Dance changed our lives,” says Robert Franks, co-founder and chief operating officer of Kick Game, a seller of exclusive, rare and sold-out trainers, with outlets in six of the UK’s biggest cities, plus Milan.

“We went from eight of us to 180 [employees] in a year-and-a-half. We went from £1.9m revenue to £45m last year – £24m of that was Jordan shoes.

“Our customers used to be 80% men. After The Last Dance, we were 50-50. White women started buying Jordans for the first time. Everyday people started buying them, particularly [reissued] Jordan 1s. That shoe appeals to everyone.”

In 2021, Sotheby’s auction house sold the earliest known Jordan/Nike shoes for $1.47m. This week, bidding opens on a pair of signed Air Jordan XIII “The Last Dance” trainers, worn by Jordan during the 1998 NBA finals. Those have an estimate of $2m to $4m, making them highly likely to be the most expensive ever auctioned. (Size 13, if you’re tempted.) “Jordan leads the way for the rest of the streetwear market,” says Brahm Wachter, vice president, head of streetwear and modern collectables, at Sotheby’s. “What helps drive the market is a longing for a certain era. When you think about Michael Jordan in 1985, lacing up his Air Jordan 1s, that gives ‘sneakerheads’ an incredible sense of nostalgia.”

Maybe, but people feel nostalgia for all kinds of things – seldom for that sort of money. To the majority of the population for whom trainers represent nothing more than a comfortable alternative to other shoes, the whole thing can be hard to get your head around.

“In 20 years’ time, it won’t be so much of a conversation,” Wachter says. “It’s very similar to stamps or comics or first-edition books, things that are created in mass that have gained, through time, a certain cultural importance to people, and therefore are valuable.”

Franks says the secondary trainer market has become the largest unregulated industry in the world. “It’s a phenomenal asset class – people are buying them and just holding them,” he says. “Wine, whisky, watches … there’s nothing that has outperformed sneakers in the last three or four years. I don’t see that changing. Sneakers are art now. They’re more than just shoes. And Jordan has led the way.”

But why Jordan particularly? It’s easy to find people who’ll wax lyrical on a once-in-a-generation athlete or riff on various technical innovations across the line: the air bubble on the III, the reflective tongue on the V, the ballistic mesh upper and carbon fibre spring plate on the XI. But even Jordan himself wasn’t particularly enamoured by some designs. For his final game at Madison Square Garden in March 1998 – his favourite place to play, as he says in The Last Dance – he chose to reprise his Jordan 1s. “By half-time, my feet were bleeding.”

Others offer a more pragmatic view. “What drives consumer interest is that, for the most part, Nike limit how many pairs they put in the marketplace,” says the veteran sporting goods and retail industry expert Matt Powell, of the consulting firm Spurwink River.

“It’s about selling out and scarcity, not the popularity of Michael Jordan. The whole key is to keep supply below demand.”

While Air is likely to further inflate the Jordan mythology – in reality, it was Jordan’s agent, David Falk, who brokered the deal, not Nike’s Sonny Vaccaro; and by most accounts it was his father not his mother who persuaded their son to sign – it is tremendous fun.

Made with Jordan and Nike’s endorsement, the film was announced during this year’s Super Bowl in an ad slot that cost $7m.

Like all things Jordan, an appropriately large number.