Ronaldo won the Professional Footballers' Association player of the year and young player of the year at a dinner in London. He's the first man since Aston Villa striker Andy Gray in 1977 to win both awards in the same season.
Ronaldo beat Chelsea striker Didier Drogba for the honor, with United teammate Paul Scholes finishing third. The other contenders were United winger Ryan Giggs, Liverpool midfielder - and last year's winner - Steven Gerrard, and Arsenal midfielder Cesc Fabregas.
"It is a special night," Ronaldo said. "It is amazing and a big honor for me to win trophies like this in the English Premier League. I am very proud.
"My colleagues have voted for me and that is fantastic because the players know the qualities of players."
The 22-year-old Portugal international has been a key member of United's side this season as it bids to repeat its 1999 treble of English Premier League, European Champions League and English FA Cup trophies. He's scored 21 goals for United so far this season.
"I want to keep working hard and getting better because these trophies have now given me more motivation," Ronaldo said. "At this moment, I am consistent. I am more mature now and I am playing better."
Ronaldo's future at United was uncertain at the beginning of the season after he clashed with United teammate Wayne Rooney in the World Cup quarterfinal match between Portugal and England in July. He publicly considered leaving but was persuaded to stay.
"Everything is right this season and I am really enjoying it," said Ronaldo, who signed a five-year contract April 13.
"I am still young and I am learning more every day. I have much time to learn more and improve myself. I try to improve all aspects of my football - not only in training but also in games."
Ronaldo is the first United player to win the senior award since Ruud van Nistelrooy in 2002. Rooney has won the young player of the year award the past two seasons.
Fabregas finished runner-up in the young player category, with Tottenham winger Aaron Lennon third. Rooney also was among the finalists for that award, along with Reading striker Kevin Doyle and Manchester City defender Micah Richards.
Man United also contributed eight players to the Premier League team of the year and manager Alex Ferguson was given a PFA Special Merit Award.
Ronaldo joined United in August 2003 from Sporting Lisbon after Ferguson had watched him play a friendly against the Red Devils.
"When we saw him play in a preseason friendly for Sporting against us, at halftime I knew we had to get him and I said to (then chief executive) Peter Kenyon 'we are not leaving the stadium until we get the boy'," Ferguson said.
"At this moment in time, I think he is the best player in the world and his season has been incredible."
The Premier League team of the year was: United goalkeeper Edwin van der Sar; United defenders Gary Neville, Nemanja Vidic, Rio Ferdinand and Patrice Evra; midfielders Giggs, Scholes, Ronaldo and Gerrard; and Drogba and Tottenham's Dimitar Berbatov as the two strikers.