But he wasn't looking for a selfie or an autograph. Instead, the then 13-year-old was there to give out his business cards.
Now 16, the London-based entrepreneur is a self-confessed sneaker obsessive and decided from an early age that he wanted to combine his two passions: trainers and football.
And he's made quite a business of his passion.
In the last three years, he has become one of the most foremost suppliers of rare sneakers and clothing to football stars all across Europe, sourcing exclusive items and then selling them on for profit.
While most kids' biggest concern is perhaps which video game they want to buy, Gissing was busy starting his business.
"I was obsessed," Gissing tells CNN Sport. "I wanted to have all of the latest shoes and all of the latest designer or Hyped or new models, and it was a case of obviously my parents weren't going to spoil me and buy me whatever I wanted, so I just needed to get a bit of extra capital, a bit of extra cash to be able to afford my own pairs of shoes.
"I realized I could do that by reselling trainers. So what I started doing was queuing up outside sneaker stores in London and buying shoes and flipping them for £20, £50 pounds on top.
"I'd queue up for hours outside, waiting for Yeezys, Jordans, whatever the new high release would be, and I flip it on eBay and Depop, one of these small interfaces where reseller meets reseller."
The teenager isn't the only one making a name for himself by trading on the desire for exclusivity. There are a number of other personal shoppers, including the likes of Sam Morgan and Joe Franklin, whose expertise are employed by high-profile footballers and musicians.
Those hours Gissing spent waiting in line for new releases and making new contacts paid off thanks to a chance encounter with US tennis star Jack Sock at Queen's Club, which stages a Wimbledon warm-up event in west London.
After asking Sock for a photo, the former world No. 8 noticed that Gissing was sporting a pair of rare shoes. "Nice sneakers, kid," he told the teenager.
"I just said: 'I can get you a pair,'" he recalls. "I knew I could get him the pairs that I was wearing."
At the time, Gissing hadn't yet created his official business Instagram page 'Plug Leon' -- a "plug" is somebody who is able to source rare and exclusive items -- so Sock put in his shopping request via Gissing's personal account.
"He placed the order for I think it was three or four pairs of really rare off-white Nike trainers," he says. "I went to his house where he was staying before Wimbledon -- he actually won the Wimbledon doubles that year -- and I delivered him the shoes."
Now, Gissing's business was up and running.
"He was very happy and that's when I started the 'Plug Leon' Instagram because he wanted to shout me out on Instagram," says the 16-year-old.
