Ji-sung's yakuza-subduing past revealed in JTBC's 'Apartment' Episode 4

JTBC's Apartment aired its fourth episode on July 19, 2026 at 10:30 PM. The show has held No. 1 among all weekend non-terrestrial programs since its premiere.

Episode 3, which aired July 18, pulled 5.6% average viewership in the Seoul metropolitan area and 5.4% nationwide per Nielsen Korea. That's up 0.7 percentage points from the first episode the previous Saturday, marking a new Saturday high for the series.

Park Hae-gang (Ji-sung) threw himself into a building representative election to get his hands on 17.8 billion won. He first emerged as a local hero by sorting out a delivery crisis inside the apartment complex. Then residents accused him of assault. The truth came out in time: he had been trying to protect a security guard. He won the election.

Episode 4 goes further back. Hae-gang's time as the head of HK Trading, an illegal gambling establishment, is put on screen. He subdues armed gang members with his bare hands while receiving a Japanese VIP at the venue, then closes the encounter with a handshake and a smile once the situation is over. The production team confirmed his past connection to a Japanese yakuza boss will be central to the episode, asking viewers to watch how "the fantastic spectacular past of a former boss becomes a variable in the current 17.8 billion won hunting operation."

Ji-sung worked through detailed rehearsals with the martial arts director and co-actors, checking every movement before cameras rolled.

Apartment is written by Kim Yun-young and directed by Jo Yong-won.