In March 2016, after gaining attention with his supporting role in the historical drama Six Flying Dragons, Park signed with BH Entertainment.

[11] In 2017, Park made a breakthrough in his career when he landed the lead role in the drama series Prison Playbook after director Shin Won-ho saw his performance in the play Male Impulse.

[19] In November 2020, Park appeared in prima ballerina Kim Joo-won's stage production Sagunja – Seasons of Change, which combined acting and dancing.

Back in 2014, Kim saw Park practicing for the Korean production of Nick Dear's Frankenstein and had expressed a wish to work with him in the future.

[22] In 2021, Park gained international fame after playing Cho Sang-woo in the first season of the Netflix series Squid Game.

[24] In 2022, Park appeared in three Netflix productions: Yaksha: Ruthless Operations,[a] Money Heist: Korea – Joint Economic Area, and Narco-Saints.

[2] Later that year, he successfully hosted an episode of Saturday Night Live Korea, ranking first on the list of most buzzworthy performers on OTT shows.

[31][32][33] In 2024, Park starred in Simon Stone's stage production of The Cherry Orchard, alongside actress Jeon Do-yeon.