Netflix has confirmed the simultaneous production of Seasons 2 and 3 of Trauma Center and announced the cast. Ju Ji-hoon, Choo Young-woo, Yoon Kyung-ho and Jung Jae-kwang are returning, while Jung Ye-in is joining the series. Actor Ha Young played trauma team nurse Cheon Jang-mi in Season 1. Ha Young will not appear in Seasons 2 and 3. Jung, who was cast through an audition, will take over the role. Cheon is a veteran nurse on the trauma team.

Ha Young's departure follows controversy over her great-grandfather's pro-Japanese actions. Ha Young said on KBS 2TV's Problem Child in House that her family had included doctors for 4 generations. Criticism followed when her great-grandfather's past became known. Ha Young said she learned of her great-grandfather's pro-Japanese actions while reviewing relevant records. Ha Young apologized for speaking lightly about her family history on the program. Netflix said in September that it respected her position and that she would not appear in the subsequent seasons.

The series begins with Baek Gang-hyeok, a surgeon who worked in war zones, joining a struggling trauma team. Played by Ju, Baek helped revive the team in Season 1 and receives a new assignment in Season 2. The new season follows Baek and the team as they try to secure time to save patients amid larger disasters and unpredictable emergencies. Obstacles within the medical system are also part of the story.

Drawn by Baek's surgical skill, Yang Jae-won joined the trauma team in Season 1 and grew while treating critically ill patients. Once known by a nickname given to him by Baek, he progressed through the designation 'No. 1' and earned recognition as a doctor. The new seasons continue his story as Baek's emerging successor. Yoon reprises Han Yu-rim, who has been promoted to head of planning at Hankuk University Hospital.

Lee Do-yun, who directed Season 1, will write and direct Season 2. Lee and writer Tomasi will work on the Season 3 script. Trauma Center is based on a web novel of the same name by Hansaniga. Season 1 premiered on January 24, 2025, reached No. 1 on Netflix's global non-English TV chart within 3 days, and appeared in the platform's TOP 10 lists in 63 countries.