In a crowd of bouncy, excited kids, there stood young Denis Shapovalov, staring up at Roger Federer.

The fair-haired little boy from Richmond Hill, Ont., squirmed eagerly as the Swiss tennis star navigated through a hefty throng of fans at Toronto's Rogers Cup, scribbling autographs. Then just as the tennis-crazy kid thought his turn would arrive, Federer gave the crowd a parting smile and was whisked away. Shapovalov burst into tears.

Today, Shapovalov tells that childhood story with a laugh. He's now 17 and the newly crowned junior Wimbledon champion – just the third Canadian in history to win a Grand Slam. He's back home for just two days after last Sunday's whirlwind experience at the All-England Club, so he's spending them with family at the small tennis academy they operate. The gregarious teen is now the No. 2-ranked junior in the world, and the same kids he's known at this academy for years look up at him now like he once did to Federer.

Today, Shapovalov is cool but unmistakably excited as the little tennis campers mill around him. He's about to get his first opportunities on the ATP Tour. Federer was a junior Wimbledon champion, too – back in 1998 at age 16. But junior slam winners don't always go on to successful pro careers.

Maybe Shapovalov will skyrocket up the rankings like Milos Raonic (one of his heroes) and Genie Bouchard once did, providing the nation with must-watch TV and building on this golden age for Canadian tennis. His modest homegrown story is compelling, a talent cultivated by his mom, once a national team player in the former Soviet Union. The likable lefty appears to have the sort of fiery game, on-court charisma and poster-boy looks that could make him wildly marketable – if he produces on the big tour.

A junior slam title does open some doors. Shapovalov has an invitation to play Wimbledon qualifiers next year with the pros. He has earned a wild card to his first ATP Tour event this weekend, the Citi Open in Washington, D.C. Later this month, the young Canadian will play at York University's Aviva Centre – a stone's throw from where he grew up – making his first Rogers Cup appearance.

But it's still just one chapter in the long, unpredictable and often gruelling tennis journey that first winds through events on the ITF Junior Circuit, ITF Futures and the ATP's Challenger Tour. Shapovalov is still a long way from competing weekly on the ATP Tour with the likes of Federer and Raonic. His ATP singles ranking is currently No. 372.

"I can remember watching Federer win Grand Slams on TV when I was a kid, trying to put myself in his shoes," said Shapovalov, seated with his parents in the office of their family-run tennis academy in Vaughan. They are below a framed photo of Shapovalov posing with the 17-time Grand Slam champion, taken two years ago when he lucked into being a lefty hitting partner for the star at Rogers Cup.

"My training is all paying off right now – I also won three Futures events this year and made the semis of a Challenger. I have so much confidence right now."

Many promising youngsters leave home for prestigious tennis academies in Europe or the United States, or as Milos Raonic did, to train full time at Tennis Canada's National Training Centre in Montreal. Shapovalov stayed with his close-knit family to hone his skills, starting under the tutelage of his mother.

Tessa Shapovalova was a tennis standout herself on the national team in the former Soviet Union (Russian last names traditionally often add an 'a' at the end for women). As the Union was collapsing, she and husband Viktor moved to Tel Aviv, where she eventually coached. They had their first son Evgeniy there, then three years later, along came Denis.

"We liked Tel Aviv, but I felt it was dangerous there for the boys, so we left for Canada in 1999 right after Denis was born," said Ms. Shapovalova, who sports the same lean build and blond hair as her son. "We came from Israel to Toronto with two little ones, and we didn't know anyone. I barely spoke English; Viktor not at all. Two weeks after we arrived, I got a job teaching tennis."

She began at the Richmond Hill Country Club and stayed about 10 years, also introducing her sons to the sport there.

"As soon as Denis grabbed a racquet at age 5, I couldn't move him off the court – he played with big kids, little kids, anyone," said Ms. Shapovalova. "I used to say to my older son at the end of the day, 'Want to hit with me?' and often he was tired after a long day and didn't want to. But Denis would say, "Me, I will Mom."

The mother encouraged him to play a style that she felt suited his athleticism and assertiveness. She taught him to play aggressive, go to the net and make big shots.

"Opponents were lobbing balls over his head when he was a young boy going to the net, and I always told him, 'Denis, one day you will grow and you're going to get those,' " said Ms. Shapovalova. "We never based it on results or winning back then. We asked him to play real tennis. We knew he would be tall and strong some day and the style would fit his personality."

At age 8, the strong youngster started separating his hands to hit one-handed backhand shots.

"A lot of people told me, 'You shouldn't let him do that; it's too difficult at this age,' " recalled Ms. Shapovalova. "I said, 'Well he has this naturally, so let him do what he wants.' "

The boy was fascinated with his mom's collection of trophies and medals and fixated on earning his own hardware. She loaned him one of hers, telling him he could keep it only until he won one of his own. They stuck to their convictions about playing his game, regardless of results. Eventually the trophies came.

"I wasn't a kid who won every tournament I was playing and I think that helped me – it motivated me a lot to know what it felt like not to win," said Shapovalov, who today stands six feet tall. "I learned to absolutely love the feeling of winning a tough match on a tough point, or figuring out how to come back when I was down and win ugly. Walking off the court with a W just made me so happy."

The costs of his training and equipment were escalating, and they tried to get his name out there, hoping maybe a sponsor could help. They made video highlight reels to post on YouTube. The clips showed the 8 year old scampering around the court in baggy shorts with a Federer-style bandanna tied around his blond locks, banging back smooth-looking forehand shots and one-handed backhands with his mother on the other side of the net.

Tennis Canada invited him to do some training in Toronto in one of its junior national programs, so he did that, too, from ages 9 to 11.

"They had more of a group approach there, and my vision was a little different," said Ms. Shapovalova. "I'm a coach and I felt he needed more individual work instead."

As he improved, it became difficult to get her son enough court time at the Richmond Hill club, so she left her coaching job there. Eventually the family decided to open its own academy, called Tessa Tennis, so he could train any time.

The small indoor facility opened in 2012 in an industrial neighbourhood in the northern Toronto suburb, and teaches kids in small-group settings. Viktor manages and operates the school, while Tessa is the head coach.

"I didn't think sending him off to another academy was the best way," said Ms. Shapovalova. "We wanted to keep Denis in a good environment at home and in regular school."

Shapovalov would attend school by day in Richmond Hill and then head directly to the club after class, often eating dinner in the car, to train long into the evening. They even tried home-schooling for a couple of years.

"This place, it's become my second home, for sure," said Shapovalov, looking down and fiddling with the beaded bracelet he always wears, which reads DON'T STOP FIGHTING.

As he approached age 13, his training needs and strength on the court became too much for Tessa.

"After two hours of training with him, I was exhausted, and I still had to coach my other students," said Ms. Shapovalova. "I needed to separate the mother from the coach."

His parents began to build him a team. They hired Adriano Fuorivia, a former manager of tennis development for Tennis Canada, to be his personal coach and travel with Shapovalov while his parents stayed home to run the academy. Since Shapovalov hasn't officially signed an agent yet, Fuorivia's job extends beyond the court.

"I know it's not easy for a family to trust someone else when the parent has been the coach, but they put their trust in me to push him every day," said Fuorivia, still his coach four years later. "I have never worked with anyone near the level Denis has reached today, but we have a great working relationship. I'm the one with him 24 hours a day on the road, staying on top of what he eats and when he sleeps."

They added specialists who work with Tennis Canada's junior players – strength and conditioning coach Clement Golliet and Nicholas Martichenko, who provides injury rehabilitation.

Two sponsors have come on board to help the family with the weighty tennis costs. First, Andrzej Kepinski joined, a promoter of past events such as the Molson Tennis Challenge and McEnroe vs. Borg. He also advises the family as sponsors and agents come calling. Then the husband-and-wife team Mary Pat and Bob Armstrong lent a hand. He's a former player who once received financial help himself, and is now the chairman of an investment firm; Mary Pat is the founder of several Ontario charities. Both Kepinski and the Armstrongs have a history of backing up-and-coming Canadian players.

Shapovalov remains a Grade 11 student at Stephen Lewis Secondary School in Thornhill, but now takes his studies online.

Results have followed on the court. He was Canada's U18 national outdoor champ last August. He's won three Futures titles so far in 2016 and lost in the semis of the Junior French Open (a loss which he says frustrated and then motivated him toward Wimbledon). He was also on the team that helped Canada win its first-ever Junior Davis Cup last December.

That three-player team, which also included rising stars Felix Auger-Aliassime and Benjamin Sigouin, was "a special bunch," according to team captain Oded Jacob. Auger-Aliassime would go on to make the final of the junior French Open in June. The three close friends have pushed one another – all part of the next crop of Canadian talent.

Jacob was struck by the maturity of Shapovalov, who wrote the captain a long and gracious note after the victory, reflecting on everything he had learned during Junior Davis Cup.

"Denis has a lot of variety in his game, which allows him to create points from different areas of the court," Jacob said. "He's a vocal leader; he steps up in big moments and wants to win points on his terms. It's a beautiful mix that he has – an attractive style of play on court and a great personality, and he's very loyal to the people around him. It's so difficult to predict what's to come for any player, but when you win a junior slam, it's definitely a sign that you have something."

Shapovalov has yet to digest all that happened last Sunday. He hoisted the boys' trophy just before Andy Murray defeated Raonic in the men's final, then lost in the doubles final with Auger-Aliassime on a day some called the biggest in the history of Canadian tennis. There was a trophy ceremony with Prince William and Kate Middleton, the Duchess of Cambridge, a whirlwind tuxedo fitting, and a trip to the Wimbledon Champions Ball, where he had his photo taken with Murray.

"He looks good visually, he plays a really charismatic style of tennis and he's a good talker," tennis analyst Chris Bowers said on Sportsnet. "It makes me think that if this guy gets to the top, he will be a real character in the game."

Canadian media have bombarded Shapovalov with interview requests, but he couldn't squeeze in many before flying off to play in Washington.

"I'm trying to stay humble, because if I don't keep producing results, all of this goes away, so I want to focus on the people close to me – my family and my team, they mean everything to me," said Shapovalov. "I want to inspire younger kids, just like Milos inspired me. I want to be like Milos one day, playing in the final at Wimbledon."