Park first appeared through Mnet's Hot Blood Men, a documentary-style reality program that showed the future members of One Day, split as idol groups 2AM and 2PM, in training.
 Park, finishing at the top spot with the most fan votes, became the leader of 2PM.
On September 4, 2008, 2PM debuted with the song "10 Out of 10" (Korean: 10점 만점에 10점; Revised Romanization: Ship Jeom Manjeome Ship Jeom) on the music program M!
Countdown after the release of their first mini-album, Hottest Time of the Day, a few days prior.

Aside from 2PM's music activities, Park created the song "Jeong" (Korean: 정) with Yeeun of the Wonder Girls for the original soundtrack of the television drama Conspiracy in the Court, and featured on V.O.S's "To Luv...".
He also participated in special stage performances, such as Navi's "Heart Damage" (Korean: 마음이 다쳐서; Revised Romanization: Maeumi Dachyeoseo) on May 3, 2009, and K.Will's "One Drop per Second" (Korean: 1초에 한방울; Revised Romanization: Il Choe Hanbangul) on June 20, 2009.
In addition to Idol Show and Wild Bunny with fellow 2PM members, he also became a regular cast member in several variety programs, including Star King and Introducing a Star's Friend.
In August 2009, he and Kara band member, Nicole Jung, became the new hosts for a cultural variety show called Nodaji.

On September 4, 2009, unfavorable comments towards Korea were found on Park's personal Myspace account from 2005.
The comments, written in English to a friend, were translated by Korean media, quickly spreading across hundreds of news articles.
Park expressed deep remorse and shame over his forgotten words and issued an official apology, explained the unhappiness that he experienced during his early days as a trainee in an unfamiliar country where he lacked family, the ability to easily communicate, and an understanding of the culture.
Although outraged protesters demanded that Park should be removed from 2PM, JYP Entertainment's CEO, Park Jin-young, stated on September 7, 2009, that he was going to continue as a part of the group.
The following day, Park announced on his official fancafe that he would be leaving the group to calm the situation and return to his hometown, Seattle, Washington.
He also apologized to the other 2PM members, and promised that he would "come back a better person".
Park Jin-young then confirmed that 2PM would continue as a six-member group.
Additionally, due to the sensitive topic of Park's departure, all 2PM members were withdrawn from their regular appearances on variety shows, and the final episode of their reality show, Wild Bunny, was postponed indefinitely.
Park's vocals would not be removed from the older songs he promoted with 2PM, but he would be absent from the newer tracks, and the remaining six members of 2PM re-filmed their music video for "Heartbeat" without Park on October 31, 2009.

2PM's first official album was titled 1:59PM, to symbolize Park's absence, according to the six remaining members.
Through their acceptance speeches at end-of-year award shows for "Again & Again", the members thanked Park and reiterated their wish for his return.
At the Mnet Asian Music Awards, the group paid homage to him during their performance of "Again & Again" with a spotlight shown over his usual position in the dance formation and his lines left unsung.
Park first appeared through Mnet's Hot Blood Men, a documentary-style reality program that showed the future members of One Day, split as idol groups 2AM and 2PM, in training.  Park, finishing at the top spot with the most fan votes, became the leader of 2PM. On September 4, 2008, 2PM debuted with the song "10 Out of 10" (Korean: 10점 만점에 10점; Revised Romanization: Ship Jeom Manjeome Ship Jeom) on the music program M! Countdown after the release of their first mini-album, Hottest Time of the Day, a few days prior.
Aside from 2PM's music activities, Park created the song "Jeong" (Korean: 정) with Yeeun of the Wonder Girls for the original soundtrack of the television drama Conspiracy in the Court, and featured on V.O.S's "To Luv...". He also participated in special stage performances, such as Navi's "Heart Damage" (Korean: 마음이 다쳐서; Revised Romanization: Maeumi Dachyeoseo) on May 3, 2009, and K.Will's "One Drop per Second" (Korean: 1초에 한방울; Revised Romanization: Il Choe Hanbangul) on June 20, 2009. In addition to Idol Show and Wild Bunny with fellow 2PM members, he also became a regular cast member in several variety programs, including Star King and Introducing a Star's Friend. In August 2009, he and Kara band member, Nicole Jung, became the new hosts for a cultural variety show called Nodaji.
On September 4, 2009, unfavorable comments towards Korea were found on Park's personal Myspace account from 2005. The comments, written in English to a friend, were translated by Korean media, quickly spreading across hundreds of news articles. Park expressed deep remorse and shame over his forgotten words and issued an official apology, explained the unhappiness that he experienced during his early days as a trainee in an unfamiliar country where he lacked family, the ability to easily communicate, and an understanding of the culture. Although outraged protesters demanded that Park should be removed from 2PM, JYP Entertainment's CEO, Park Jin-young, stated on September 7, 2009, that he was going to continue as a part of the group. The following day, Park announced on his official fancafe that he would be leaving the group to calm the situation and return to his hometown, Seattle, Washington. He also apologized to the other 2PM members, and promised that he would "come back a better person". Park Jin-young then confirmed that 2PM would continue as a six-member group. Additionally, due to the sensitive topic of Park's departure, all 2PM members were withdrawn from their regular appearances on variety shows, and the final episode of their reality show, Wild Bunny, was postponed indefinitely. Park's vocals would not be removed from the older songs he promoted with 2PM, but he would be absent from the newer tracks, and the remaining six members of 2PM re-filmed their music video for "Heartbeat" without Park on October 31, 2009.
2PM's first official album was titled 1:59PM, to symbolize Park's absence, according to the six remaining members. Through their acceptance speeches at end-of-year award shows for "Again & Again", the members thanked Park and reiterated their wish for his return. At the Mnet Asian Music Awards, the group paid homage to him during their performance of "Again & Again" with a spotlight shown over his usual position in the dance formation and his lines left unsung.
Jay Park