The 24-year-old's impressive performances throughout the season have seen him attract interest from Real Madrid, but United are planning new talks with the Spaniard this week as they aim to extend his current deal beyond next summer.
In winning the fans' award, known as the Sir Matt Busy Player of the Year, he has become just the fourth player in United history to take home the trophy in two consecutive seasons, following in the footsteps of Roy Keane, Ruud van Nistelrooy and Cristiano Ronaldo.
"I want to say thank you to my teammates, they have been fantastic this season," De Gea said on receiving the award. "We have a great dressing room and I would like to say thank you very much."
Louis van Gaal was among those who gave his vote to De Gea and the United manager admits he as been impressed by the goalkeeper's development at Old Trafford this term.
"I think he is popular with the fans," Van Gaal told MUTV.
"In the beginning of the season I observed him, I analysed him and then I saw his progress this season.
"I have to say it is a fantastic development from him. As a manager, you look at it from that perspective and that is why David De Gea has impressed me the most."
De Gea: "I want to say thank you to my team-mates. They have been fantastic this season - I love them!" #mufcpoty— Manchester United (@ManUtd) May 19, 2015
Ryan Giggs also backed the former Atletico Madrid keeper, saying: "It has to be David De Gea. He's won us so many games."
Meanwhile, Wayne Rooney revealed his Player of the Year vote went to Ashley Young.
“He's been incredible this season,” said the United captain.