Park began his solo career with his first fan-meet tour, and by releasing an EP, O'Clock, following the end of Wanna One's activities as a group.

He also resumed his acting career and known for his roles in Flower Crew: Joseon Marriage Agency (2019), Love Revolution (2020), At a Distance, Spring Is Green (2021), and Weak Hero Class 1 (2022).

[7] Park debuted as a child actor, participating in musicals like Peter Pan (2007–2009), The Harmonium in My Memory (2010), and Radio Star (2010–2011), and small stints in television dramas Jumong (2006–2007), The King and I (2007–2008), Kimchi Cheese Smile (2007–2008), Iljimae (2008), and more.

Due to a knee injury, he did not make it to the final line up of Fantagio's boy group Astro and subsequently transferred to Maroo Entertainment.

He experienced a sudden rise in popularity after going viral as "wink boy (ko: 윙크남)", after the introductory "It's Me (Pick Me)" stage on M Countdown, even before the show had started airing.

Wanna One disbanded on December 31, 2018, and officially completed activities after their sold out 4-day final concert series 'Therefore' that ran from January 24 to 27 at Gocheok Sky Dome.

[22] The same month, Park was cast in JTBC's historical drama Flower Crew: Joseon Marriage Agency,[23] which was aired on September 16.

[24] Park received praise for his great acting skills and got many positive reviews for his first drama since the start of his career as a soloist.

Beginning in South Korea, the tour was set to span cities in several countries including Seoul, Hyogo & Tokyo, Macau, Bangkok, Taipei and Jakarta.

Park Jihoon took his first lead role in the Kakao M's web drama Love Revolution, an adaptation of the popular webtoon of the same name.

[38][39] Park starred in the lead role of the KBS college drama At a Distance, Spring is Green which aired from June 14 thru July 2021.

[50] Park received overwhelming praise from both critics and online communities for his portrayal of Yeon Si-eun, with some of his highlight scenes going viral on various social media sites such as Tik-Tok and Twitter.

The role has been called a "rediscovery of Park Ji-hoon" as the idol singer's cute and bubbly image was nowhere to be found in his performance.

[51] When asked about the casting of Park, creative director Han Jun-hee revealed that shortcake (the production company) CEO Lee Myung-jin originally suggested the idol actor for the role after being amazed with his performance in At a Distance, Spring Is Green.

[102] A special event was held where customers would receive an exclusive bromide when purchasing April Skin hair products over 15,000 won.

[103] Park along with fellow Wanna One member Ong Seong-wu was selected as a model for CLAVIS and their line of sports bracelets on April 20.

[105] The same month, Park and fellow former Wanna One member Bae Jin-young were selected as the new advertising models for youth make-up brand, I'M MEME.

[citation needed] In October, Park collaborated with Tous on the 'Toss Love Me' perfume that was made to commemorate the 100th anniversary of the brand's founding.