Park has become an unsung hero at United, dispelling doubts over the validity of his move from PSV Eindhoven in 2005 to seal a central place in Sir Alex Ferguson's plans.
"I have enjoyed every minute of my time at United," he said.
"I am delighted to be part of the club during this latest stage in its history - with another exciting young team being built.
"I am looking forward to playing my part in keeping United at the top of the game."
Ferguson revealed during United's pre-season tour of North America that the club had offered Park a new contract.
The 30-year-old quickly indicated a willingness to sign and now the loose ends have been completed ahead of the Premier League opener at West Brom.
Having played a part in four league title triumphs, plus three League Cup wins and a Club World Cup, Ferguson clearly views Park as a major figure in the new team that is emerging at Old Trafford, especially as his decision to retire from international combat earlier this year has substantially reduced the tiring hours spent travelling back to the Far East.
"Ji has been an important player for us for a number of years now," said the Scot.
"He has great ability and energy and in recent seasons has added the knack of scoring important goals in big games.
"He is a popular member of the squad and his experience at domestic and international level is invaluable for the younger players."
Source: Team Talk
Source: Team Talk