Park Hae-soo debuted through the theater play "Annapurna," in October 2007. Originally active on the stage, the actor began to familiarize himself through the small screen with series including "Six Flying Dragons," (2015-16) on SBS and "Prison Playbook," (2017-18) on tvN. He was part of the global fame of Korean content through Netflix Korea's original series "Squid Game," (2021), in which he portrays player No. 218, or Cho Sang-woo, who joins the protagonist to risk his life to play a set of deadly children's games in the hopes of winning huge prize money.