First Man

Synopsis

In 1995, twin sisters Oh Jang-mi and Ma Seo-rin were born. One of them was forcibly taken by Chae Hwa-young from their birth mother, Jeong Suk-hee. The child was later brought into Chairman Ma's house, where Hwa-young claimed her as her own child with Dong-seok. Ultimately, she joined the Chairman Ma's family and fulfilled her desire to enter the Dream Group. As the twins grow up, they lead vastly different lives, one is the spirited and righteous, and the other is a spoiled heiress. One day, when the twin sisters finally meet, they later decide to switch identities to uncover the hidden truth. Ma Seo-rin, who took on Oh Jang-mi's identity, was in a coma after an accident orchestrated by Chae Hwa-young, intended for Jang-mi. Jang-mi later assumed Seo-rin's identity to gather evidence against Chae Hwa-young, to crush and bring down the evil woman. As Kang Baek-ho and Kang Jun-ho, two brothers, become entwined with Jang-mi, romance, rivalry, and secrets slowly unfold.

Cast and characters

Main

Hahm Eun-jung as Oh Jang-mi / Ma Seo-rin

Oh Jang-mi: The older of the twins who is a warm-hearted and principled young woman with a culinary dream, working hard to open her own restaurant. She inherited her mother's culinary skills. Her dream is to meet Chef Kang Jun-ho and become his apprentice, and she even got an interview to work with him, but in the end she couldn't make it. One day, Jang-mi's world is turned upside down when she discovers that Chae Hwa-young, someone she once admired, is actually her arch-enemy. After uncovering the truth, a burning desire for justice consumes her, and Jang-mi sets out to punish Hwa-young for her heinous actions.

Ma Seo-rin: The younger of the twins, who grew up as the spoiled and troublesome granddaughter of the Dream Group, is a reckless woman who fears nothing in life and has everything she wants. Separated from her birth mother and twin at birth by Chae Hwa-young, she was raised as her own, unaware of the hidden truth. Her goal is to win Kang Jun-ho's heart and make him her man. After being mistaken for Jang-mi, she's driven by curiosity to find her, and unexpectedly becomes the first to discover that she has a twin, leading her to dig into Hwa-young, who isn't biologically related to her.

Oh Hyun-kyung as Chae Hwa-young

A former top star who hides her tough ambition and strong will behind a beautiful smile. She is the daughter-in-law and CEO of the Dream Group, and Seo-rin's mother, who's ruining another woman's life to achieve her ambition of taking over the Dream Group. Fueled by her cruelness, she'll stop at nothing to keep Jang-mi from the Chairman and Seo-rin, even if it means silencing her forever.

Yoon Sun-woo as Kang Baek-ho

A lawyer at Law Firm Leeho. His strong sense of justice compels him to help those in need. He is always kept girls at a distance, but Jang-mi is the one who gets him to open his heart. When Hwa-young's orchestrated accident almost kills Jang-mi, he's the first to rescue her. Baek-ho is her constant ally in the pursuit of justice, truth, and revenge.

Park Geon-il as Kang Jun-ho

Supporting

Jung So-young as Jeong Suk-hee

Jang-mi and Seo-rin's biological mother. She was once a bright and intelligent woman, but Hwa-young ruined her life. To protect the other twin, she took a risk and suffered a tragic accident that left her with the mental capacity of a five-year-old.

Kim Hak-seon as Oh Bok-gil

Jang-mi's adoptive father. He grew up with Suk-hee in an orphanage. After a tragic accident happened to her, he took care of her and her child and loves them like they're his own family.

Lee Ki-chang as Oh Tae-pyeong

Jang-mi's adoptive older brother and the son of Bok-gil. He loves singing and chases his dreams, but repeatedly gets scammed and loses hope. He is Baek-ho's best friend.

Jeon A-reum as Oh Tae-sook

Bok-gil's daughter, who is Tae-pyeong's older sister, and Jang-mi's adoptive sister.

Kim Ra-hee as Yeon Bo-ra

Tae-sook's daughter.

Lee Hyo-jung as Ma Dae-chang

The chairman of the Dream Group.

Kim Young-pil as Ma Dong-seok

Jang-mi and Seo-rin's biological father, and Suk-hee's lover, who is the heir of the Dream Group, has gone missing for many years.

Lee Jae-hwang as Lee Kang-hyuk

Hwa-young's trusted secretary.

Ahn Joo-in as Yang Geom-sun

Production

Development

The First Man is directed by Kang Tae-heum, who previously helmed Desperate Mrs. Seonju (2024–2025), and Seo Hyun-joo of The Second Husband (2021–2022), and Ahn Ji-young co-wrote the screenplay. Produced by MBC C&I and DK Entertainment and planned by Jang Jae-hoon, the series revolves around a woman driven by desire, who devastates another woman's life to attain her goal, while the other woman seeks revenge by choosing a new path. Director Kang stated that the title 'First Man' could also be called 'First Love'. He aimed to convey that love can help overcome any obstacle or hardship through this series.

On April 24, 2026, the series was extended by 20 episodes, from 120 to 140 episodes.

Casting

In October 2025, Hahm Eun-jung, Oh Hyun-kyung, Yoon Sun-woo, Park Geon-il, and Kim Min-seol were officially confirmed to star. Additionally, Hahm previously led the KBS2 daily drama Queen's House (2025), and Kim Min-seol, a participant from Single's Inferno season 4, made her leading role debut in the series. The next month, it was announced that Lee Hyo-jung, Jung So-young, Jung Chan, and Lee Jae-hwang had joined the cast.

Release

The First Man was set to premiere on MBC TV in the second half of 2025 and air in an MBC Monday–Friday timeslot. The series was originally scheduled to premiere on December 1, 2025, but was postponed. In November 2025, a script reading was revealed, and it was officially confirmed to premiere on December 15.

Original soundtrack