Shin Si-ah

Shin was born on 12 May 1998, as an only child. She started considering becoming an actress after seeing the musical Carmen in her first year of high school. Over the next two years, she watched four musicals per week, which helped build her confidence in acting. When she was a high school student, her goal was to go to the Department of Theater and Film, and then to participate in plays. Her goals were to join a production company and to make independent films. She then enrolled in the Department of Theater and Film at Hanyang University.^[3][4][5]

From 2018 to 2019, Shin was listed as a cast member of the TV Mini Series My Darling Boyfriend.^[6] In 2019, Shin was cast in the short film Prasad. The film centers on a girl who survives a bus accident alone and is subsequently bullied on social media, leading to her transformation into a real witch. The film was screened at the 18th Mise-en-scène Short Film Festival.^[7][8]

In 2020, Shin was cast as the lead in The Witch: Part 2. The Other One following an audition process with odds of 1,408 to 1. The first and second rounds consisted of non-face-to-face video auditions. After advancing to the third round, she met director Park Hoon-jung for an in-person audition. She then had approximately five or six subsequent meetings with the director before ultimately being selected. The entire audition period lasted about three months.^[9] At that time, it was reported that Shin was affiliated with the agency Andmarq as a rookie actress.^[10]

On March 13, 2022, Shin signed an exclusive contract with Andmarq.^[11] On June 15, the movie The Witch: Part 2. The Other One where Shin is the lead, premiered.^[12] On July 17, Shin had her first solo pictorial shoot since her debut with W Korea.^[13]

On January 20, 2025, Andmarq confirmed Shin's casting in the movie The Old Woman with the Knife, where she plays a younger version of the main character, Hornclaw.^[14] The film was subsequently invited to the Berlinale Special section of the 75th Berlin International Film Festival.^[15] On February 14, Shin joined Chef Edward Lee, Byun Yo-han and Go Ah-sung in a variety show called Edward Lee's Country Cook.^[16]

Shin made her drama debut on tvN's Resident Playbook as Pyo Nam-kyung, a first year resident doctor, alongside Go Youn-jung, Kang you-seok, and Han Ye-ji. It premiered on April 12, 2025.^[17] On June 9, Shin signed an exclusive contract with Management Soop.^[18] She starred in the romance film Even If This Love Disappears From the World Tonight directed by Kim Hye-young, based on the novel of the same name.^[19] It was released theatrically on Christmas Eve 2025,^[20] and is also available to stream on Netflix since February 2026.^[21][22]

In 2020, Shin appeared in a cosmetics brand advertisement as a ballet teacher.^[23] On 23 June 2022, Shin was selected as the main model for Plus X's modern Asian skincare brand Diponde.^[24] In 2023, Shin, was selected as model for Coca-Cola's hydration drink Toretta!.^[25][26]

In 2024, Mongdol, a brand that pursues natural minimalism, released a pictorial for its 2024 summer collection campaign with Shin. The pictorial was part of the "Mongdol X Sia" campaign.^[27]