West Ham have reportedly agreed to cover Lingard's wages for the duration of his time at London Stadium and pay a £1.5million fee to United.
The 28-year-old was allowed to leave to find more regular first-team football, having only made three appearances under Ole Gunnar Solskjaer this season.
Lingard played under Hammers boss David Moyes when he was in charge of the Red Devils and is looking forward to working with him again.
He told West Ham TV: "I'm excited. It's another new chapter in my life. Nothing is guaranteed but I've come here to work hard and help the team and bring my experience.
"That's the main aim. I just want to enjoy my football and get back playing again and get my feet back on the pitch.
"There were lots of clubs involved but, for me personally, I felt this was the right move. I've obviously had a previous relationship with the manager as he was at Man U and I've played under him before, so he knows my qualities and what I can bring to the team.
"I know a couple of the players as well – I know Dec [Rice] very well from the England side – and I feel I can really settle in here quickly."
Moyes said of his new signing: "I've seen him play as a young boy, when he was still a wide player on the right, and I've seen him play off the left.
"He's played for England as a number 10, he's played for England as a number eight, and I actually think if we needed him as a false nine, he could do that as well.
"We're bringing in that versatility, I've wanted to try to get an energetic team at the moment and Jesse has been known for his work-rate and effort, so I think he'll fit in nicely with what we've got.
"I hope he brings us a little bit of quality too, and a winning mentality from Manchester United."
Lingard's best season came in 2017-18, when he had a hand in 19 goals (13 scored, six assisted) in all competitions for United – it was one more goal involvement than he had managed in his two prior campaigns for the club combined.
Anthony Martial (20), Marcus Rashford (21) and Romelu Lukaku (36) were the only two United players to play a role in more goals that season, while his first senior England strike arrived in March 2018.
Things quickly went downhill, though. After an assist in a 3-1 win at home to Huddersfield Town on Boxing Day in 2018, Lingard did not register another Premier League goal involvement for United until scoring against Leicester City on the final day of last season. It ended an incredible run of over 28 hours on the pitch with a goal or assist in the top flight.
Lingard also experienced the longest drought of his club career in 2019, with 307 days separating goals against Arsenal in the FA Cup in January and versus Astana in the Europa League in November.
The arrival of Lingard comes after the high-flying Hammers completed a permanent deal for attacking midfielder Said Benrahma.
The Blades, walloped 8-0 by Newcastle six days earlier, had the air of a team already resigned to relegation just seven matches into the season.
Their visit to the London Stadium was a welcome one for West Ham, who had suffered back-to-back defeats by Manchester City and Liverpool.
The only surprise was that the Hammers did not score more, although it could have been an entirely different story had the Blades opened the scoring after 10 minutes when Cameron Archer turned Kurt Zouma in the area, only for Nayef Aguerd to slide in and block his shot.
That was pretty much their only glimpse of Alphonse Areola’s goal in the first half as West Ham went for the jugular.
First Bowen out-muscled James McAtee on the byline and cut the ball back for Soucek, who blazed over the crossbar.
Then, from a James Ward-Prowse corner, Bowen had a header saved at point-blank range by Wes Foderingham, with Aguerd’s follow-up headed off the line by Luke Thomas.
The goal West Ham had been threatening arrived in the 24th minute when Vladimir Coufal crossed low into the penalty area.
Bowen had timed his run into the box to perfection and arrowed a first-time finish past Foderingham for his sixth goal in the Premier League this season, and his first at home.
West Ham, sensing they could fill their boots just like Newcastle did against the Blades a week earlier, poured forward with Michail Antonio curling a shot just wide and Soucek narrowly off target with a glancing header.
Nine minutes before the interval they doubled their lead after the visitors lost possession as they tried to play out from the back.
Emerson Palmieri’s pass along the edge of the box found Antonio, who unselfishly slipped in Soucek to slot the ball home.
After the break Archer had a half chance in the area but his shot was deflected over the crossbar.
And a miserable afternoon for the Blades got even worse when captain John Egan limped off.
They should have been further behind when Bowen rounded Foderingham and pulled the ball back, but Antonio could not find the finish.
Aguerd headed wide from another Ward-Prowse corner before Blades striker Oliver McBurnie could have set up a nervous finish for the hosts, only to see his header fly the wrong side of the near post.
The issue happened against Dallas United in the The Soccer Tournament event on Thursday.
Dalles have withdrawn from the £1million competition following the allegation, which came towards the end of the game with Dallas leading 2-0.
Former Hammers Anton Ferdinand, Carlton Cole, Matt Jarvis, Marlon Harewood, Zavon Hines and Jimmy Walker are among those taking part in North Carolina.
It is unclear what was said – or to which player – but Ferdinand reportedly told media at the game the Hammers walked off due to racism.
A statement from TST read: “After conducting an investigation into the final moments of the match between West Ham United and Dallas United, we have concluded that Dallas United violated TST’s code of conduct.
“We have been in dialogue with leadership from both clubs and we are all aligned that the best path forward is Dallas United withdrawing from competition. All parties involved are unified in wanting to make a statement against racial insensitivity.
“We seek to run an event that is not only fiercely high stakes for all competitors, but also one in which all competitors feel safe and protected. As a result, tomorrow’s game between Dallas United and Far East United has been cancelled.”
The referee reportedly told players he did not hear what was said, before West Ham decided to walk off.
Dallas United wrote on Twitter: “In light of the shadow cast by an opposing player’s accusation during tonight’s match, the Dallas United players unanimously decided to withdraw from the remainder of the competition.
“Our coaches and staff fully support the team’s decision. We thank @TST7v7 for the opportunity to compete in the tournament.”
Wolves, Borussia Dortmund and Wrexham are among the teams taking part.
The 28-year-old has endured a horrible start to life at the London Stadium following his January loan move from Manchester City, where his career stalled following his 2022 transfer from Leeds.
After being culpable for goals conceded against Bournemouth and Manchester United, he then was sent off in the Hammers’ 2-0 defeat at the City Ground for picking up two yellow cards in the space of two minutes and 56 seconds.
Phillips was desperate for his move to be a “fresh start” and wants to put it right.
“They say bad luck comes in threes, so let’s hope I’ve had my three pieces of it and I can kick on now,” he said.
“I wanted this to be a fresh start, to really get my head down and go for it. It’s not gone as I would have hoped. Everyone can see that.
“But I know football. I’m experienced enough to know that if I get my head down and grit my teeth and do the basics right that things will turn.
“It’s easy to say, but now I’ve got to do it.
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“There are certain things you need to do on a football pitch. OK, I was training with the best team in the world, but games get you sharper.
“You can train all you like but you are never going to really get match fit and match sharp unless you play games, do you?
“So, that’s the reason I’m frustrated and gutted.”
West Ham were trailing to Taiwo Awoniyi’s first-half opener when Phillips picked up two quick bookings in the second half, the first for grappling with Nicolas Dominguez and then fouling Morgan Gibbs-White.
He tried to speak to referee Thomas Bramall after the game, but left the City Ground frustrated.
“I’m annoyed with myself over the first booking. He’s got my shoulder and I’ve tried to push him off – perhaps next time I should kick the ball at him to make my point,” he added.
“I was frustrated and we were losing. But it’s something I’ll learn from.
“With the second, I’ve not made any contact with Morgan (Gibbs-White). He’s jumped up and that’s fair enough but – honestly – I didn’t make any contact.
“I’ve waited outside the referee’s room to have a chat with him.
“I wanted to have a word but it’s been half an hour now and he’s not come out. I don’t know if he knows I was there or not. I didn’t want to batter him. I just wanted to have a conversation with him about it.
“But it looks like I’m going home now without saying my piece and I’m just disappointed – more so because I’m working hard to get myself back into a position where I can help and now I’ve got to miss a game.”
Forest won for the first time in the Premier League this year to boost their survival chances.
Defender Neco Williams said: “The focus was the three points. We’ve been through a tough spell these recent few weeks. We dominated throughout. Scoring twice and a clean sheet, not a lot more you can ask for.
“I’m delighted for Taiwo. He’s been working so hard to get back on the scoresheet. He took his goal so well.
“It was a collective. There was a clean sheet and a bonus to get two goals for the attackers, all good.”