The goalkeeper has rejected rumours of a potential move back to Spain after coming into his own in his second season following a disappointing first year at Old Trafford
The Spaniard won plaudits for a fine second season with United, winning the league title, earning a spot in the Professional Footballers' Association Team of the Year and finishing third in United's Player of the Year award.
The improvement comes after losing his place to second-choice Anders Lindegaard for periods of his debut term and the early stages of last season, prompting speculation linking him with a move back to Spain, namely Barcelona - rumours the 22-year-old was quick to deny.
"I have a contract. I feel more and more happy at United," he told reporters. "I faced normal difficulties [in my first season] – a new country, language, a different league – but through hard work I managed to adapt.
"I am very happy in Manchester."
De Gea and his team-mates are preparing for life under a new manager next term after Sir Alex Ferguson ended his 26-year tenure with the club.
And the Spanish goalkeeper is excited by the prospect of working with the incoming David Moyes.
He added: "I felt great sadness when I heard about Ferguson's goodbye. It will be strange not to see him on the bench or on the training ground. He is everything at Manchester United. He is Manchester United.
"Moyes had done a great job at Everton and now all of us have to support him. To substitute Ferguson is a huge target but if they chose him to do it, it is because he is prepared."