He gained early recognition by competing in the first season of K-pop Star in 2012, where he finished in sixth place before signing with JYP Entertainment.

Jae Park was born in Buenos Aires, Argentina and moved to Cerritos, California in early childhood.

[2] He graduated from Cerritos High School and later studied political science at California State University, Long Beach.

Throughout high school and university, he ran a YouTube channel, "YellowPostItMan", where he uploaded vocal-and-guitar song covers as a hobby.

JYP Entertainment (JYPE) offered Park a contract at the end of the show to join the company as a trainee for an upcoming band.

On May 10, 2020, Park's activities with Day6 were placed on hold as the group took a hiatus to focus on their health, the day before their sixth extended play The Book of Us: The Demon, with the lead single "Zombie", was released on May 11, 2020.

On September 21, 2020, Park and 2PM's Nichkhun took on roles as members of crime-fighting boyband "4 2 Sing" in season three of Big Hero 6: The Series.

[17] On April 19, 2021, after the group's hiatus for their health, Day6, including Park, released their seventh extended play The Book of Us: Negentropy, with the lead single "You Make Me".

Park performed at Head in the Clouds Festival 2021 on November 6 to 7, 2021 at the Brookside at the Rose Bowl in Pasadena, California.

[20] The same day, JYP Entertainment announced that Park would be leaving the band and ending his exclusive contract with the company for personal reasons.

[25] Park performed at Head in the Clouds Festival 2022 on August 20 to 21, 2022 at Brookside at the Rose Bowl in Pasadena, California.

[26][27] On October 28, Park performed as a guest artist at the MAX - North America Tour 2022 show at The Wiltern in Los Angeles, California.

It included the pre-release single, "In My Civic", as well as releasing for the first time on streaming platforms three of the songs that had previously been released in 2020 as part of the eaJ Project: "LA Trains", "50 Proof", and "Pacman", with the titles of "LA Trains" and "Pacman" being re-stylized in lowercase.

On May 10, 2020, JYP Entertainment announced that Day6 would be taking a hiatus due to the mental health concerns of some members.

On September 15, 2020, Park initiated From Friends, a project partnered with Represent, selling clothing and other merchandise.

[35] The campaign raised $100,000 which was donated to the Jed Foundation, which helps provide free mental health resources to teenagers and young adults.