Always brash and outspoken, leading to fall outs with many, Van Gaal divided opinion throughout his career, but his record of developing and blooding young talent is one major positive he will always be remembered for.
Here's a starting XI of superstar players Van Gaal gave first team debuts to...
Victor Valdes (GK)
Goalkeeper Victor Valdes, a player who had first joined the Barcelona youth ranks at the age of 10, was given the nod by Van Gaal during his second spell at Camp Nou in 2002/03.
Valdes had previously played for Barcelona C and Barcelona B in the preceding seasons but started as Van Gaal's number one until the more established Roberto Bonano came back into the team. Valdes eventually played 535 times for Barça, winning 21 trophies.
Carles Puyol (DF)
The first of the 593 games Camp Nou legend Carles Puyol played for Barcelona came in October 1999 after Van Gaal opted to promote the shaggy-haired academy graduate from the second string to the first team, initially as a right-back.
Puyol later transitioned to centre-back and inherited the captaincy under Van Gaal protégé Frank Rijkaard in 2004. His trophy haul when he retired in 2014 included three Champions League titles and six La Liga crowns.
Holger Badstuber (DF)
Holger Badstuber is the one that might have been for Bayern Munich and Germany, had years of serious injuries not taken their toll on the once bright talent that Van Gaal made a regular starter from the age of just 20.
Having never played for Bayern's first team, Badstuber played 49 times during the 2009/10 season as Van Gaal steered the squad to the Champions League final. He remained a regular after the Dutchman left, but later began to succumb to injuries.
David Alaba (DF)
David Alaba began training with Van Gaal's Bayern squad midway through the 2009/10 campaign and was just 17 years of age when he made his debut in a Champions League game against Fiorentina en-route to that year's final.
The Austrian defender played nine games for Van Gaal and was still only 18, on loan at Hoffenheim, when the Dutchman was sacked in April 2011. Alaba then became an immediate starter back at Bayern the following season and has never looked back.
Edgar Davids (MF)
Edgar Davids was part of the famous golden generation Van Gaal gave rise to Ajax, culminating in Champions League glory over a fearsome AC Milan in the 1995 final, with the tenacious Davids part of the group that returned to the final 12 months later.
The midfielder's debut came early in Van Gaal's managerial career, just a few weeks into the 1991/92 season, and was affectionately nicknamed 'The Pitbull' by his boss. Davids later famously played for Juventus and is remembered as an enduring legend of the 1990s.
Clarence Seedorf (MF)
Another youngster crucial to Ajax's Champions League success, Clarence Seedorf made his debut under the watchful eye of Van Gaal in November 1992 at the age of 16 and had just turned 19 when he became a European champion in 1995.
Seedorf was one of the first to leave that great Ajax side. But he went on to win further Champions League trophies with Real Madrid and AC Milan and is still the only player to have won the competition with three different clubs.
Xavi continued to develop and again played for Van Gaal when the Dutchman returned to Catalonia for in 2002. He went on to win four Champions League titles and seven further Spanish crowns, while his 767 games for Barcelona is an all-time club record.
Andres Iniesta (MF)
Second on Barcelona's all-time appearance list is Andres Iniesta, another midfielder handed his debut by Van Gaal. The very first of his 674 games came when the then 18-year-old started against Club Brugge in the Champions League in October 2002.
Iniesta didn't have much time to work under Van Gaal, who was sacked a few months later, and it was eventually under Frank Rijkaard that he started to become a regular. The player went on to finish second in the 2010 Ballon d'Or standings, and third in 2012.
Jesse Lingard (FW)
Despite winning the FA Youth Cup in 2011 and having been on the fringes of the first team for a number of years, Jesse Lingard was a surprise name on the Manchester United team-sheet for Van Gaal's first Premier League game in charge of the club in August 2014.
Unfortunately, who played as a wing-back, that day ended in injury after just half an hour. But Van Gaal brought him back into the fold just over a year later and he finished the 2015/16 by scoring the winning goal in the FA Cup final. Three years on, he is increasingly important.
Patrick Kluivert (FW)
An 18-year-old Patrick Kluivert was handed his senior Ajax debut in the 1994 Dutch Super Cup, the curtain raiser for the 1994/95 Dutch season. By the end of that campaign, Kluivert was the player Van Gaal turned to make the difference in the Champions League final.
Having turned 19 by then, the striker came off the bench and struck the famous late winner. He eventually went on to play for Van Gaal again at Barcelona and remains the Dutch national team's third highest goalscorer of all time.
Marcus Rashford (FW)
Manchester United forward Marcus Rashford was the last success story of Van Gaal's youth policy, handing the 18-year-old a senior debut in difficult circumstances against Midtjylland during his final few months in charge at the club.
Rashford repaid the faith by scoring twice, repeating the feat again on his Premier League debut against Arsenal. He has now played over 150 games for the club, was handed the number 10 shirt last summer, and already has 31 England caps.