The Penthouse: War in Life

Penthouse tells the story of wealthy families living in Hera Palace and their children at Cheong-ah Arts School.

Shim Su-ryeon (Lee Ji-ah) is an elegant, wealthy woman who has a tragic past. Her husband is Joo Dan-tae (Uhm Ki-joon), a successful businessman. She later learns that he is hiding something from her.

Oh Yoon-hee (Eugene) comes from a humble family background. She has had bad blood with Cheon Seo-jin (Kim So-yeon) since high school. She is a famous soprano whose father is the head of Cheong-ah Arts School. They get involved in a love triangle relationship with Ha Yoon-cheol (Yoon Jong-hoon).

All of them have grand ambitions and desires for their children and would do anything for them. However, their lives begin to crumble as a young mysterious woman named Min Seol-ah (Jo Soo-min) crashes to her death during a party at Hera Palace. While the Hera Palace residents try to cover up the fact that she died on the premises, they cannot help but suspect each other for the murder.

• Lee Ji-ah as Shim Su-ryeon, a graceful, dignified woman who is humane and kind, despite her immense wealth. She and her husband live in the penthouse, making her the queen of the social clique at Hera Palace.
• Kim So-yeon as Cheon Seo-jin, a wealthy woman who is the epitome of showy and arrogant and who harbors warped ambitions.
• Eugene as Oh Yoon-hee, a woman whose dreams have been stunted by her lack of money and power. With gritted teeth, she has had to take on any job and humiliation to support her daughter's ambitions. Oh Yoon-hee does everything in her power to move up socially so that her child can enter Cheong-ah Arts School.

• Um Ki-joon as Joo Dan-tae, husband of Shim Su-ryeon, a genius of real estate who rakes in money with every investment he makes.
• Kim Young-dae as Joo Seok-hoon, Dan-tae's twin son
• Han Ji-hyun as Joo Seok-kyung, Dan-tae's twin daughter
• Na So-ye as Joo Hye-in, Su-ryeon's daughter
• Jo Soo-min as Anna Lee/Min Seol-ah, Joo Seok-hoon and Joo Seok-kyung's tutor/biological daughter of Shim Su-ryeon

• Yoon Jong-hoon as Ha Yoon-cheol, husband of Cheon Seo-jin, an ambitious man who believes that a man must hold wealth and power. He is the head of surgery in the VIP department of a hospital.
• Choi Ye-bin as Ha Eun-byeol, Seo-jin and Yoon-cheol's daughter
• Jung Sung-mo as Cheon Myung-soo, Seo-jin's father
• Ha Min as Kang Ok-gyo, Seo-jin's mother
• Shin Seo-hyun as Cheon Seo-young, Seo-jin's younger sister
• Ahn Tae-hwan as Seo-young's husband, Seo-jin's brother-in-law

• Kim Hyun-soo as Bae Ro-na, Yoon-hee's daughter
• Hwang Young-hee as Yoon-hee's mother-in-law
• Unknown as Bae Ho-cheol, Yoon-hee's ex-husband, Ro-na's father

• Shin Eun-kyung as Kang Ma-ri, a woman who has recently come into wealth and leads a secretive double life.
• Jin Ji-hee as Yoo Jenny, Ma-ri's daughter[18]
• Heo Sung-tae as Yoo Dong-pil, Ma-ri's husband, Jenny's father. Currently in prison.

• Bong Tae-kyu as Lee Kyu-jin, the only son and momma's boy of a wealthy family of judges and lawyers, and is himself a lawyer.
• Yoon Joo-hee as Go Sang-ah, wife of Lee Kyu-jin and a former announcer.
• Lee Tae-vin as Lee Min-hyeok, Kyu-jin and Sang-ah's son
• Seo Hye-rin as Wang Mi-ja, Kyu-jin's mother

• Park Eun-seok as Gu Ho-dong/Logan Lee, a nice PE teacher at Cheong-ah Arts School, who fights for justice and Anna's older adoptive brother.
• Byeon Woo-min as Congressman Jo Sang-heon
• Ha Do-kwon as Ma Du-ki, music teacher at Cheong-ah Arts School
• Kim Dong-kyu as Secretary Jo
• Han Seung-soo as Orphanage Director Min Hyung-sik
• Lee Cheol-min as Yoon Tae-joo

• Kim Byung-hyun as Joo Dan-tae's best friend pitcher[19]
• Ki Eun-se as Journalist Kim Jung-min[20]
• Kim Sa-kwon as Detective in charge of Oh Yoon-hee's investigation[21]
• Ki Tae-hwa as Su-ryeon's ex-husband, Seol-ah's father

• Jun Jin as ?[22]
• Ryu Yi-seo as ?[22]
• Lee Sang-woo as ?[23]
• Lee Si-eon as ?[24]
• Bada as ?[25]
• Kim Soo-min as ?[26]
• Ahn Yun-hong as ?[26]

The production cost of this series is 31 billion won, 670 million won per episode.[27] In September 2019, planning and preparation for the series started.[28]

Season 1 was extended by one episode to enable the series to end on a Tuesday.[29]

On November 24, 2020, the series was officially renewed for a second and third seasons of twelve episodes each. It was also announced that the final seasons would air on the Friday–Saturday time slot compared to the first season which aired on Monday–Tuesday time slot.[30]

Eugene was cast in one of the lead roles, consequently returning to the small screen after a five-year hiatus.[4] Casting for the series started in December 2019,[31] and finalized in January 2020.[32] Due to scheduling conflicts, Shin Sung-rok left the cast in February.[33] Originally scheduled to take place in February 2020, the first script reading was pushed back to March due to COVID-19 pandemic.[34] Um Ki-joon joined the cast in April.[35]

Filming was halted on November 24, 2020 as one of the supporting actors was tested positive for COVID-19. The next day, it was reported that Um Ki-joon, Park Eun-seok and Bong Tae-gyu tested negative for COVID-19.[36]

The prelude teaser was released by Seoul Broadcasting System on September 22, 2020.[37] The teaser was termed as "[Mood teaser] a brilliant bloody prelude".[38][39] Season 1 premiered on October 26, 2020 on SBS TV and airs every Monday and Tuesday at 22:00 KST.

Going by big data analytics firm Good Data Corporation, as of second week of December, The Penthouse: War in Life is at first place with 27.82% surge in media mention.[45] As per big data analytics firm Good Data Corporation's ranking for the third week of December, The Penthouse: War in Life led with a 27.66% surge in media mentions for the fourth straight week.[46]