The 52-yr-vintage, who has signed a three-year agreement, faces a massive mission to revive the Red Devils fortunes after a 5th consecutive trophyless season.
The Dutchman will become the fifth permanent supervisor at Old Trafford on account that Alex Ferguson's retirement in 2013 despatched the 20-time English champions into decline.
Ten Hag is on route to win his third league identify with Ajax and took the four-time European champions to the semi-finals of the Champions League in 2019 for the primary time in 22 years.
"It is a first rate honour to be appointed supervisor of Manchester United and I am hugely excited by means of the undertaking ahead," said Ten Hag.
"I recognize the records of this super club and the passion of the lovers, and I am without a doubt decided to expand a crew capable of delivering the success they deserve.
"It might be difficult to leave Ajax after those first-rate years, and I can assure our lovers of my entire dedication and recognition on bringing this season to a a hit end earlier than I move to Manchester United."
United take a seat sixth inside the Premier League, 23 factors at the back of leaders Manchester City, and are not likely to qualify for next season's Champions League.
The membership have been searching out a permanent manager seeing that Ole Gunnar Solskjaer changed into sacked in October.
Ralf Rangnick become appointed period in-between boss for the the rest of the season, however the German has been not able to inspire any development in United's overall performance.