The Sir Matt Busby award has been presented to the supporters' favourite star since 1988 when Brian McClair was the inaugural winner. Valencia is the eighth overseas player to win it, following Eric Cantona, Ruud van Nistelrooy, Andrei Kanchelskis, Javier Hernandez, Nemanja Vidic, Gabriel Heinze and Cristiano Ronaldo.
"I am very happy to receive all three awards," said Valencia on stage, also referring to his Goal of the Season victory.
"After last night, the longest night of my life, I will take heart from this.
"There should be 20 of these awards because all of my team-mates deserve one. I'd like to thank them and to thank my fans at home in Ecuador and Manchester United fans everywhere."
Valencia received 37 per cent of votes cast on the club's official seven websites, with Wayne Rooney finishing as runner-up wiyth 24 per cent and the returning Paul Scholes in third place on 12 per cent.