The veteran midfielder won four Premier League titles and the Champions League with the club, but ongoing concerns about his knee has forced him to hang up his boots
The 33-year-old, who represented South Korea 100 times at international level, revealed his decision at the JS Football Center in Seoul - the headquarters of Park's own foundation, which helps develop football infrastructure around the world.
"I've been mulling retirement since February, and I've concluded that my knee won't hold up for another season," Park said.
"I have no regrets about my career. I do think about what might have been if I hadn't been injured, but I have no feelings of disappointment or sorrow as I leave the sport."
Park spent the past season at PSV - his first European club - on loan from QPR and made 27 appearances across all competitions, scoring two goals as the Dutch side finished fourth in the Eredivisie.
But the South Korean, who captained his country from 2008 until his retirement from international football in 2011, made his name at United - playing 203 matches and scoring 28 goals between 2005 and 2012.
Park won the Premier League four times with United and was also part of the Champions League title-winning team in 2008.
Having started his professional career with Kyoto Purple Sanga, Park won the 2002 Emperor's Cup with the Japanese outfit, before claiming two Eredivisie titles with PSV in his first stint in the Netherlands.