Prior to being elected as mayor, Park was a community and social justice activist, serving as a member of the Truth and Reconciliation Commission.

[10] In 1994, he was a principal founder of the nonprofit watchdog organization People's Solidarity for Participatory Democracy (PSPD), which monitors government regulatory practices and fights political corruption.

[11] In 2002, Park stepped down from PSPD to run The Beautiful Foundation, a philanthropic group that promotes volunteerism and community service and addresses issues of income inequality.

[13] In 2006, as an offshoot of The Beautiful Foundation, Park founded the Hope Institute, a think tank designed to promote solutions arising from grassroots suggestions for social, educational, environmental, and political problems.

[18] Early in 2012, Park was accused of illegally manipulating the army draft health checkup to have his son sent to a favorable post.

[20] As a consequence of the successful implementation of the plan, Park was recognized in South Korea and internationally as a leader of the Sharing City concept.

[26][27] He was a vocal critic of then-President Park Geun-hye and participated in huge rallies against her in central Seoul that led to her impeachment and ousting on corruption charges in 2017.

Park also sent inappropriate texts and photos to the victim, including pictures of himself in his underwear as well as obscene late-night messages over the Telegram app.

[35][36][37][38] The independent National Human Rights Commission of Korea (NHRC) found that Park's words and actions toward his secretary constituted sexual harassment under the country's laws.

[39][40] Park's cell phone was reported as turned off in the Seongbuk District of Seoul, with his daughter finding a will-like note.

[45][33][46] Park's family accepted a state funeral, held at Seoul City Hall and streamed online on July 13, 2020.