Sacked after just ten months into his six-year contract, the decision marked the start of nearly a decade of desperation, as Manchester United appointed big names with little direction or long-term plan.
Succeeding Sir Alex Ferguson and emulating what he achieved at the club was always likely to be the impossible job for David Moyes, and that is exactly what it proved to be.
On Sunday evening, David Moyes will return to Old Trafford as the manager of West Ham United. Now in his second spell at the London club, his dismissal from Manchester United sparked a nomadic coaching journey, which took him to the likes of Real Sociedad and Sunderland.
It was a journey that Moyes needed to follow to recover from what a period that will forever tarnish his achievements in the game.
Ironically, his record is relatively comparable to his successors, and it seems that Manchester United have now accepted that there is no quick-fix with their continued support for Ole Gunnar Solskjær.
Manchester United were sitting seventh in the Premier League table when David Moyes was sacked in April 2014 following a 2-1 defeat to his former club Everton.
Missing out on a UEFA Champions League place was unthinkable at the time. But that was the reality for a club that had become comfortable in their continued success.
The troubles of the post-Sir Alex Ferguson era at Manchester United are well-documented, but David Moyes has regrouped, recovered and returned to West Ham United.
His determination to prove himself despite the biggest setback of his career has taken West Ham United to fifth place. They now sit just six points below Manchester United as the two teams prepare to meet at Old Trafford.
David Moyes has moved on from his Manchester United 'failure'
David Moyes has been back to Old Trafford as a manager since his sacking. But this weekend, he returns as a manager enjoying a successful season while once again showing the credentials to coach in the Premier League that earned him the job in the first place.
Although he has never won there as a visiting manager, he will hold his head high. While his emotions could be equally heightened, it is no longer about the past for the man from Glasgow.
Agreeing a six-year contract at Manchester United with the support and recommendation of Sir Alex Ferguson, David Moyes had every reason to believe he would be given time to build the foundations of a new era at the club.
However, the promise of longevity failed to materialise, and when the share price fell as quickly as the team slid down the Premier League table, the panic button was pressed.
To his credit, David Moyes dusted himself down and quickly returned to management.
Heading to Spain with Real Sociedad, he took himself out of the scrutiny of the British press with the focus on learning from his experience and taking what positives he could from a decision that could have easily brought his career at the top level to an end.
Now heading towards his 1,000th game as manager, David Moyes has finally achieved redemption from his Manchester United failure. The scars will remain with him, but they will now serve as a sign of what can be achieved against adversity rather than a symbol of career destruction.
David Moyes will understand the pressure that Ole Gunnar Solskjær finds himself under more than anyone else in this most volatile of professions. While he will wonder what might have been had he been allowed to continue with the Manchester United project, he will not envy his opposite number in the same way he would have had on his first return to Old Trafford in 2016.
West Ham United are enjoying a successful season, and a return to European competition is very much in their control.
David Moyes is responsible for what West Ham have achieved this season, and he can be proud of how is team are performing under his leadership. Manchester United are nothing more to David Moyes now than the next challenge in his ambition for the season.
Management at the very highest level requires a steely determination of strength and self-belief. David Moyes became a figure of fun following his dismissal from Manchester United; it was harsh and undeserved, but his character has shown his resilience to recover and succeed.
Meanwhile, Manchester United face a tough test against their former manager on Sunday, especially that his demons from the most-turbulent and difficult times of his career have now been well and truly exorcised.
For David Moyes now, closing the gap on his former club is for West Ham United only and not for his own redemption.