Starting from April, Park toured Asia and North America for JYJ's first Worldwide Tour.Park has written and composed several songs that have appeared on TVXQ's Korean and Japanese albums.While starting her pageantry career, she met Leon Isaac Kennedy, who was a DJ and a struggling actor/writer. Motown’s Smokey Robinson served as best man at the wedding. According to a report in the , a home movie featuring Kennedy with then-husband Leon engaging in intercourse was one of the earliest known example of a “celebrity sex tape”.As a member of SM Town, he contributed to the 2007 winter album Only Love with his composition "Evergreen".Park also wrote and composed "사랑 안녕 사랑 (Love Bye Love)", featured on the group's fourth Korean studio album Mirotic.
He won "Best Newcomer Award" and "Most Popular Actor in a TV Drama" at The 47th Baeksang Arts Awards, the most prestigious entertainment awards in South Korea.In July 2009, Park and two of his TVXQ bandmates, Jaejoong and Junsu, filed a lawsuit against their South Korean agency S. After TVXQ's Japanese label announced a group hiatus in early 2010, they formed a new three member group initially known as JUNSU/JAEJOONG/YUCHUN in Japan. Both sides agreed to retiring every judicial accusation against each other and not interfering in each other's actions.In November 28, 2012, the legal battle between JYJ and S. JYJ proceeded to release The Beginning, a global album which was sung in English.Two months later, Park made his Korean debut as an actor in the hit 2010 KBS drama Sungkyunkwan Scandal (성균관스캔들).He portrayed Lee Seon Joon, a wealthy, passionable and studious nobleman, who falls in love with his fellow schoolmate—a woman disguised as a man.At the 2011 MBC Drama Awards, Park won "Best Newcomer" for his role as lead male in "Miss Ripley." In 2012, he starred in the SBS drama Rooftop Prince with Han Ji-min.Park's third role was Lee Gak, a Joseon era prince who time-travels 300 years to the present day, and also as Yong Tae-yong, third generation of conglomerate. On August 30, Park won "Most Popular Actor in TV Drama" at the 48th Baeksang Arts Awards, crowning him as the most popular actor for two years in row.After a relatively short training period of 1 year and 5 months, he made his debut as a member of the 5-member male group Dong Bang Shin Ki through SBS Bo A & Britney Spears Special Stage on December 27, 2003.From 2003 to 2009, Park performed as a member of the best-selling K-pop boy band TVXQ. Through their lawyers, the members stated that the 13-year contract was excessively long, schedules were held out without the confirmation or permission of the members, contract terms have been extended and changed without their knowledge or consent and that the group's earnings were not fairly distributed to the members.He has starred in dramas Sungkyunkwan Scandal (2010), Miss Ripley (2011), Rooftop Prince (2012), Missing You (2012), Three Days (2014) and The Girl Who Sees Smells (2015).In 2001, he won award at American Music Festival and then returned to Korea to prepare for his debut.