Park Hae-soo’s acting career started on stage with the 2007 musical Mister Lobby. In 2012, he made his small screen debut in the MBC weekend sageuk God of War. In 2017, he led the tvN series Smart Prison Living, which won him Best New Actor at the 2018 The Seoul Awards. His work in the drama also earned him a Best New Actor for TV nomination at the 54th Baeksang Arts Awards as well as an Excellence Award nomination at the 6th APAN Star Awards. In 2019, he headlined the crime film By Quantum Physics: A Nightlife Venture, which scored him Best New Actor trophies at the 40th Blue Dragon Film Awards and the 25th Chunsa Film Art Awards. In 2020, he was nominated for Best New Actor for Film at the 56th Baeksang Arts Awards for his performance in the dystopian action thriller film Time to Hunt. In 2021, he appeared in the megahit Netflix survival drama Squid Game, which received both critical acclaim and international fame.

Park Hae-soo married his girlfriend on January 14, 2019. They welcomed their first son on September 29, 2021.