It didn’t take long for Dougie Freedman’s hunch about Yannick Bolasie to pay off. Less than 30 seconds into his first appearance for Crystal Palace at Selhurst Park on 1 September 2012 against Sheffield Wednesday, the spindly 22-year-old born in Lyon to Congolese parents but raised in north-west London picked up the loose ball on the edge of the penalty box, bamboozled his marker and delivered a cross that Glenn Murray simply could not miss.

“I’ve been after that kind of player for a long time,” Freedman reflected a few weeks later. “We kept tabs on him for about six months and we were very fortunate to finally get him. We knew we needed a player of that kind of ability to go by players on the outside to create space.”

Bolasie’s path to signing for Everton for £25m, which could rise to a record fee of £30m has, a bit like his playing style, not exactly been orthodox. But, starting out at non-league Rushden & Diamonds and Hillingdon Borough, a five-year contract at Goodison Park worth an estimated £20m is rich reward for the grime-loving winger whose professional career began in the Maltese Premier League and has taken in stops at Plymouth, Barnet and Bristol City.

Tony Finnigan, who played in midfield for Palace between 1984 and 1988 before becoming an agent, remembers watching Bolasie for the first time while he was on loan at Barnet.

“He went up for a goalkick with the centre-half and both players missed the ball,” Finnigan tells the Guardian. “Everyone thought it was going to go out for a throw but he got up and sprinted to keep the ball in, did a trick and got to the byline to win a corner. Then he took the corner with his left foot.”

Suitably impressed, he sought out Bolasie after the match, arranged to meet his parents and told them he could make their son a Premier League player within three years. He wasn’t far off.

Things did not quite work out at Home Park at first but Bolasie forced his way into the Plymouth team before administration struck. With Finnigan’s help, he was purchased for just £10,000 by Palace’s current assistant manager Keith Millen, then in charge of Bristol City, after failing a medical at Watford owing to a knee injury.

“When I heard he was available, I was really excited,” said Millen at the time. “Players like Bolasie don’t become available at that price very often and it was simply too good an opportunity to turn down.”

Five years on, the Robins can expect a cheque of around £4m after inserting a 15% sell-on clause when he was bought by Freedman a year later for £350,000. When Bolasie signed, the former Scotland striker remembered telling him if he could be half as good as emerging talent Wilfried Zaha “that would be fine. Yala said: ‘I’ll be better.’”

With both wingers providing the bullets for Murray, Palace recovered from losing their first three games and had moved into the top four by the time Freedman controversially defected to Bolton at the end of October.

Ian Holloway took over but ended up just missing out on automatic promotion from the Championship. After a 0-0 draw at home in the first leg, he left Bolasie on the bench for the second leg of the play-off semi-final against arch rivals Brighton before the winger’s cross for Zaha that eventually broke the deadlock 21 minutes from time.

Yet Holloway again let him out of the starting lineup as a penalty from Kevin Phillips against Watford sealed Palace’s return to the top flight. That summer, having fulfilled his father’s dream of playing for Democratic Republic of Congo despite initially turning them down, Bolasie decided to get serious. Thanks to a new fitness programme which he attributed to his trainer Rayan Wilson in an interview with the Observer in October 2014, his body changed from a beanpole to “a beast”.

The results have been stunning. Despite failing to score a single goal – a regular bone of contention that was seized on by Bradley Wright-Phillips in their regular MC battles – Bolasie filled the creative gap left by Zaha’s £10m departure to Manchester United and his all-round performances were integral to Palace’s 11th-placed finish as they survived a season in the Premier League for the first time. Already blessed with speed and unpredictable ball skills honed by hours spent dodging the Wendy house and slide at his local playground in Willesden, the 27-year-old’s powerful physique now gives him an edge over most opponents in the strength department as well.

“It can take time for some players to reach their potential, especially if you have come through the non-league,” says Finnigan, who parted company with Bolasie after Palace’s promotion but remains on good terms with him.

“Managers in England want wingers to work hard for the team and that sometimes sacrifices what they are best at. Dougie Freedman recognised he was a maverick who needs to be shown he is trusted and that’s why he has improved so much in the last few years. His uniqueness makes him special.”

While the statistics do not exactly stand out – only nine goals in his last two seasons – Palace’s continued over-reliance on Bolasie despite the return of Zaha was underlined during his two-month absence with a back injury last season when they failed to win any of the nine Premier League games he missed. A few months earlier, Pardew had insisted he would not sell his prized asset for £40m – a suggestion that does not seem quite as ludicrous now given the fee being stumped up by Everton.

Dougie Freedman recognised he was a maverick who needs to be shown he is trusted

But while the club have always publicly insisted Bolasie was not on the market, a series of improved contracts signed each summer after switching agents has reflected a gradual move towards the exit door from both parties. The latest – worth around £60,000-a-week and signed last summer – was designed to maintain his value in anticipation of sizeable offers being received in the future.

Tottenham tried and failed to tempt Palace into selling Bolasie last summer, while Leicester also made enquiries in January after encouragement from former assistant Steve Walsh. His move to Goodison Park to become director of football prompted Everton to pick up the mantle and, with the help of the former Sunderland chief executive turned agent Margaret Byrne, who resigned over her handling of the Adam Johnson child sex abuse case, the mega-money transfer has now come to fruition.

“He fully deserves all the success that is coming his way,” Finnigan says. “At Everton he’ll be under a different kind of pressure but Ronald Koeman is the kind of manager who can take him to the next level. I’m glad Palace have got that much money because they deserve it for taking a chance on him. I feel very proud.”

Everton fans will be crossing their fingers he can maintain his upward trajectory.