Van Gaal's time at Old Trafford was somewhat underwhelming given his track record of success at clubs like Ajax, Barcelona and Bayern Munich, as well as at international level, but he did deliver the first trophy post-Sir Alex Ferguson in the shape of the FA Cup in 2016.
The Dutchman also stayed true to United values on youth development and handed debuts to 13 academy graduates during his two seasons at the helm.
Here's a look back at each one of them and where they are now...
When Van Gaal arrived at Old Trafford in the summer of 2014, Jesse Lingard had never actually played a competitive first-team game for the club. That's despite being part of an FA Youth Cup winning squad three years earlier and turning out for several Championship clubs on loan.
The winger was a surprise inclusion in the starting lineup on the opening day of the 2014/15 Premier League season when Swansea visited Old Trafford, only for injury to strike.
Lingard eventually became a regular from November 2015 onward, scored the winning goal in the 2016 FA Cup final and is now an increasingly important first team player.
Another who made his competitive United debut against Swansea on the opening day of 2014/15, Tyler Blackett had previously spent time on loan at Blackpool and Birmingham without impressing before being given his chance back at United by Van Gaal.
The Manchester-born defender went on to play a total of 12 games in all competitions, although his chances later diminished. He barely played during a loan at Celtic and now turns out for Reading after leaving United in 2016.
After formally joining the academy as a 16-year-old, Andreas Pereira was given his first taste of senior football against MK Dons in the Capital One Cup in August 2014 when United were on the end of a 4-0 humiliation.
The Belgian-born Brazilian made his Premier League debut against Tottenham a few months later, before signing a new long-term contract and being named Under-21 Player of the Year.
Pereira spent Jose Mourinho's first two seasons at Old Trafford on loan at Granada and Valencia in Spain, but has been involved under Ole Gunnar Solskjaer of late.
Reece James was virtually unknown by most United fans when his name was included on the squad list of the 2014 summer tour of America. The left-back was a regular on tour was another who was handed a proper debut in the infamous MK Dons game.
That was his only first-team appearance and subsequent loans at Rotherham and Huddersfield were followed by a transfer to Wigan Athletic in July 2015, moving on to Sunderland in 2018.
Saidy Janko was the third academy graduate who debuted in Milton Keynes. The Swiss full-back had been a rising star of the Under-21 setup leading up to his first-team bow and actually started the game, although he only lasted until half-time.
Janko never played in the Premier League for United and left for Celtic in 2015 after a Bolton loan. He is now on loan at Nottingham Forest from Porto after a previous spell at Saint-Etienne.
An injury crisis at the heart of the United defence was what led Van Gaal to hand Paddy McNair a senior debut in October 2014. Still only 19-years-old at the time, he started in the Premier League against West Ham and earned rave reviews.
McNair continued to float around the fringes of the first-team for a while until being sold to Sunderland after Van Gaal was sacked in 2016. He then joined Middlesbrough when the Black Cats were relegated from the Championship in 2018.
Tom Thorpe was the captain of the last United side to lift the FA Youth Cup in 2011 as a colleague of Jesse Lingard and Paul Pogba. Having previously spent time at Birmingham on loan, the centre-back's senior debut with his parent club came in the same game as McNair.
Thorpe left Old Trafford not long after when he moved to Rotherham. Loans at Bradford and Bolton followed, before heading abroad to play for ATK in the Indian Super League in 2017.
Teenage left-back Cameron Borthwick-Jackson was handed a senior debut by Van Gaal in November 2015 - surprise replacement for Marcos Rojo in a Premier League game.
Borthwick-Jackson continued to be heavily involved, making 14 first team appearances by the end of the season, but he hasn't played for United since and has been loaned out ever since.
Now 22 years of age, he's with Scunthorpe until June after previous spells at Wolves and Leeds.
Donald Love was only given a squad number a mere few hours before making his first-team bow against Sunderland in February 2016 - a product of the injury crisis that gripped United.
Love featured again in the first leg of the Europa League tie against FC Midtjylland, with those his only two United appearances before soon joining Sunderland.
Joe Riley was an unused substitute when United were surprisingly beaten by Midtjylland in February 2016 and was handed his first senior opportunity a few days later when Borthwick-Jackson was unable to continue against Shrewsbury in the FA Cup.
Despite an appearance against Midtjylland at Old Trafford, although he never featured in the Premier League and left Old Trafford permanently for Bradford in 2018.
Snapped up from the same junior club that produced Wes Brown, Danny Welbeck, Ravel Morrison and others, Marcus Rashford was famously thrown in at the deep end when Anthony Martial was injured in the warm-up prior to facing Midtjylland in February 2016.
The fearless striker, only 18 at the time, grabbed his chance with both hands by scoring twice. Sensationally, he scored two more against Arsenal on his Premier League debut to prove it wasn't a fluke and has been a first team star ever since.
Rashford has now played 160 games and was handed the club's number 10 shirt last summer.
United plucked Dutch defender Timothy Fosu-Mensah from the world famous Ajax academy in 2014 and he made his senior debut in the 3-2 win over Arsenal under Van Gaal in February 2016 as an early second half replacement for the stricken Marcos Rojo.
Then only 18 years of age, he gave a good account of himself and was instantly a favourite among United fans waiting to see more of him. But, three years on, that still hasn't happened after average loans at Crystal Palace and Fulham.
Former Man Utd Under-21 captain James Weir was the last of the 13 academy graduates that Van Gaal put his faith in, making his debut as a late substitute in the same game as Fosu-Mensah.
Having joined Hull for a nominal fee in 2016, the midfielder has only played 11 more senior games in nearly three years since, including an unsuccessful loan spell at Wigan.