2007–2011: Career beginnings In August 2007, Seohyun made her official debut as the youngest member of girl group
Girls' Generation. The group gained significant popularity after the release of their hit single "
Gee" in 2009. Seohyun's early solo work mostly involved songs recorded for side projects and original soundtracks. Although they did not achieve much commercial success; her duet titled "JjaLaJaJJa" with veteran singer
Joo Hyun-mi earned a "Trot Music of the Year" nomination at the
2009 Mnet Asian Music Awards. In 2010–2011, Seohyun appeared in
MBC's variety show
We Got Married 2, alongside
CNBLUE's
Yonghwa. They played a make-believe couple, portraying what life would be like if they were married. In addition, Seohyun was cast as voice actor for the Korean-dubbed version of animated film
Despicable Me (2010) and its sequel
Despicable Me 2 (2013), together with fellow member
Taeyeon. She voiced the character of Edith, who is known for her rebellious attitude.
2012–2016: TTS and musical acting In April 2012, Seohyun, along with fellow members Taeyeon and
Tiffany, formed a Girls' Generation subgroup named
TTS. Their debut
EP,
Twinkle, met with much success and became the eighth highest selling album of the year in South Korea. The subgroup went on to release two more EPs:
Holler (2014) and
Dear Santa (2015). Besides contributing her vocals to Girls' Generation and TTS songs, Seohyun began to become more active in lyrics writing. She co-wrote the songs "Baby Maybe" and "XYZ" (
I Got a Boy, 2013) and was credited as the sole lyricist for "Only U" (
Holler, 2014) and "Dear Santa" (
Dear Santa, 2015). In 2013, Seohyun debuted as an actress when she was cast for a supporting role in
SBS's drama
Passionate Love. She played Han Yu-rim, a veterinary student and first love of the male lead character. Director Bae Tae-sub said Seohyun's persona "perfectly paralleled that of her role" and "her understanding and expressiveness of the character exceeds those of a rookie actress". Seohyun, self-described as someone who likes both singing and acting, began to develop an interest in
musical theatre. She named musical actress
Ock Joo-hyun, who later became her mentor, as her main influence. Although she had wanted to be in a musical for a long time, she rejected casting offers because she felt unprepared. In January 2014, her wish was fulfilled as she accepted her first musical acting role. Seohyun made her theatrical debut in the musical,
Moon Embracing the Sun, which was adapted from the novel of the same name. Seohyun played the lead role, Yeon-woo, the daughter of a noble family who has a love relationship with both the King and his brother. In January 2015, Seohyun was cast in the role of
Scarlett O'Hara in the Korean version of
Autant en emporte le vent, a French musical based on
Gone with the Wind. She received encouraging review for her performance. Seon Mi-gyeong of
OSEN said that while Seohyun's performance cannot surpass that of
Bada, who shared the same role, her "fierce voice" complemented and successfully expressed an arrogant Scarlett O'Hara. Kim Hyun-joong of
Sports Chosun noted Seohyun's occasional "clumsy" acting, but compared her to Ock Joo-hyun during her rookie days and said that "her ability to bring emotion through song, the most important part of a musical, rivaled that of a veteran actor. Despite a short career, she endlessly showed us various colours and peculiar charms of a woman's life." From February–June 2016, Seohyun was cast in the Korean version of the musical
Mamma Mia. She played a character named Sophie, a 20-year-old bride-to-be, who hopes to find out who her biological father is on her wedding day. Kim Geum-yeong from
CNB Journal commented on Seohyun's improvement from her prior musical performances, praising her "natural acting" and "daring side" while Park Jeong-hwan from '''' claimed Seohyun's performance made the musical "all the more entertaining". Seohyun next played supporting roles in Chinese romantic film
So I Married An Anti-fan and SBS's historical drama
Moon Lovers: Scarlet Heart Ryeo; the latter earned her a Special Acting Award at the
2016 SBS Drama Awards. Tamar Herman from
Billboard noted the album presented a "new maturity" to the singer. ''Don't Say No'' debuted atop the South Korean
Gaon Album Chart. To accompany her solo release, she held a
concert residency titled "Love, Still – Seohyun", part of a series of concerts by SM Entertainment artists. After taking part in
OnStyle's web-drama
Ruby Ruby Love, Seohyun next starred in MBC's weekend drama
Bad Thief, Good Thief as Kang So-joo, a police-woman-turned-investigator who struggles to fight against the abusive officials. Her portrayal of the character earned her the Best New Actress award at the
2017 MBC Drama Awards. In October 2017, Seohyun left SM Entertainment after her contract ended. Her future activities with Girls' Generation remain in discussion. In 2018, Seohyun was cast as the female lead in MBC's melodrama
The Time as the character Seol Ji-hyun, a bright and optimistic woman who became depressed after the tragic death of her sibling. In September 2018, Seohyun announced her first fanmeeting tour,
Memories, in
Seoul,
Bangkok,
Taipei,
Osaka and
Hong Kong.
2019–2024: New agency and continued acting career In March 2019, Seohyun signed with
Namoo Actors. A year after signing with her new agency, she starred in the short drama
Hello Dracula. She played the role of An-na, an elementary school teacher who hid her emotions from her mother since the day she came out to her as a lesbian. Later that year, she starred in the
JTBC television series
Private Lives as Cha Joo-eun, a swindler who has to choose a deceptive path to survive in Korea. In February 2022, Seohyun made her debut in a movie as a lead actress in the
Netflix original movie
Love and Leashes, based on the webtoon
Moral Sense. She played the character of Jung Jiwoo, a competent public relations team member who accidentally found out her co-worker's BDSM desires. Her portrayal of the role earned her a nomination for the Best New Actress award under the Film category at the
58th Baeksang Arts Awards. In April 2022, Seohyun renewed her contract with Namoo Actors. In June 2022, Seohyun starred in the
KBS fantasy romance series
Jinxed at First, She played the character Lee Seul-bi, who has the special ability of seeing the future of any person she touches. The role earned her the Best New Actress award at the
2022 KBS Drama Awards, as well as the Best Couple Award with the male lead co-actor
Na In-woo. In September 2023, she starred in the Netflix original series,
Song of the Bandits. She played the character Nam Hee Shin, an independence activist disguised as the head of the Railway Bureau of the Japanese Government-General of Korea who has hidden her true identity.
2025–present: Departure from Namoo Actors and new agency On April 24, 2025, Seohyun ended her contract with Namoo Actors. Seohyun starred in action-horror film
Holy Night: Demon Hunters as Sharon, an exorcist and a member of the trio of demon hunters called 'Holy Night'. It was released on April 30, 2025 in 933 screens. It opened at first place on Korean box office with 121,321 admissions and a gross of US$680,433. , the film has grossed worldwide. On May 15, 2025, Seohyun signed an exclusive contract with Lead Entertainment. After three years, Seohyun return to the small screen via romantic-comedy series,
The First Night with the Duke. The series premiered on
KBS2 on June 11, 2025. She played the role of K, a contemporary college student who awakens unexpectedly inside her beloved historical romance book. She possessed the body of a supporting character in the novel named Cha Seon-chaek and unexpectedly changed the plot of the novel. Seohyun has been announced to star in the upcoming film
Seeking the King. In December 2025, Seohyun signed with new agency Dream ENT. In March 2026, Seohyun will make her debut as a violinist at the 8th Regular Concert of the Sol Philharmonic Orchestra, to be held on March 13. She will play "
Csárdás", the famous piece by
Vittorio Monti. ==Other ventures==