2006–2011: Beginnings as a child actress Kim debuted as a
child actress in 2006, playing a supporting role in the
Drama City special "Ten Minute Minor". Then, she diligently increased her appearances from
A Happy Woman (2007),
Que Sera Sera (2007),
Hometown of Legends (2008),
My Name Is Pity (2008),
Wife and Woman (2009) and
Ja Myung Go (2009). She signed a management contract with
SidusHQ in 2010. That year, she would go on to be cast in
Becoming a Billionaire and
Bread, Love and Dreams. Kim was confirmed to make her big-screen debut in
Man of Vendetta (2010) as Joo Hye-rin, a daughter of a well-respected pastor who gets kidnapped. Kim was cast through a competition of 500:1. She continued to portray the child counterparts of the female protagonists in television series such as
The Thorn Birds (2011),
The Duo (2011) and
Sin of a Family (2011). She then starred in a family comedy film,
Spy Papa, about parents and children's relationship during inter-Korean relations in 1974.
2012–2014: Rising popularity and teenage roles In 2012, Kim appeared in six works in the first half of the year: a
romantic fantasy television series,
Padam Padam; a historical comedy film,
I Am the King; a fantasy-period drama
Moon Embracing the Sun, in which she gained recognition as the younger version of the second female lead, Kim received commend from the audience and the director of how well she portrayed the
antagonist's desire realistically the drama came to rank number one in its time slot throughout its run and achieved a peak recorded viewer rating of 42.2%, thereby earning the "national drama" status Kim simultaneously became "Korea's little sister"; followed by a fantasy-comedy
Rooftop Prince in the role as an evil sister;
Love Again and a high school student whose roommate is a female idol star in
Ma Boy. Kim reunited with co-stars from
Rooftop Prince (
Park Yoo-chun) and
Moon Embracing the Sun (
Yeo Jin-goo) respectively, in a melodrama
Missing You. Being dubbed the "Queen of Child Actors" () by the Korean press, she was one of the most praised child actors of her generation. She played the role of Lee Soo-yeon, bullied by her schoolmates and called "the daughter of the murderer", who gets kidnapped and sexually assaulted while trying to save her friend. Kim and Yeo shared the highest one-minute viewer rating scene of 10.4% in the drama. She received her first acting award as "Best Child Actress" at the 1st
K-Drama Star Awards for
Ma Boy and
Missing You. and starred in
The Secret of Birth as a girl with a genius-level brain. Then, she played the younger version of
Lee Bo-young's character in the popular Korean drama
I Can Hear Your Voice. On 20 June, Kim co-host
MBC's music program
Music Core along with
Minho of
SHINee and
Noh Hong-chul. The three received much attention because of the combination of singers, actors, and broadcasters even though they initially showed a bit of immature progress, but amplified expectations of how they expressed their charms despite having different careers. She then was cast in
The Suspicious Housekeeper, a Korean
remake of the Japanese
drama,
Kaseifu no Mita. In the same year, Kim was reported along with
Kim You-jung and Yeo Jin-goo as the top three child actors who earn above-average salaries for child actors. It was reported that Kim received 4-6 million won per episode. In 2014, Kim was cast as a child actor beside
Oh Yeon-soo in the MBC drama,
Triangle. Kim challenged her first
dual role and first genre through OCN's new drama
Reset. Later, she was cast in
KBS2 special drama,
We All Cry Differently, which won the 2013 KBS Screenplay Contest.
2015–2016: Transition to leading roles and hosting In 2015, Kim made a special appearance as the sister of the male lead in
A Girl Who Sees Smells, On 18 April, Kim stepped down from her
Music Core host posts after two years. Kim starred in
KBS's school series
Who Are You: School 2015, playing dual roles as twins Lee Eun-bi and Go Eun-byul. She was awarded "Star of the Year" at the eighth
Korea Drama Awards for her performance. On 21 November, Kim held her first overseas promotion schedule at
Sunshine City,
Hong Kong. At the end of the year, Kim became the host of the
2015 KBS Drama Awards with
Jun Hyun-moo and
Park Bo-gum. In 2016, she returned to the big screen in a romance film
Pure Love opposite
Do Kyung-soo, playing the heroine of the film who has a beautiful voice but suffers from a leg injury. Kim then starred in a mystery-school web drama
Nightmare Teacher alongside
Lee Min-hyuk, playing a class president who discovers mysterious secrets of the school. The drama was filmed and featured nine students at Hosan University. The same year, Kim starred in
Park Hye-ryun's three-episode drama special
Page Turner opposite actors
Ji Soo and
Shin Jae-ha. She played the role of a "piano genius" who lost her sight after an accident. The number of video previews released in the web and mobile achieved 600,000 views which was considered "an unusual number" as a
one-act play. She was dubbed as the "Korean Wave Fairy" by the Taiwanese media. On 4 June, Kim hosted the
2016 Dream Concert with
Leeteuk and
Hong Jong-hyun. She made her next acting move in the horror-comedy ''
Hey Ghost, Let's Fight with Ok Taec-yeon, and played as the 13-year-old Princess Deokhye in the film The Last Princess, for which Park A-reum of K-pop Herald praised Kim for her in-depth emotional acting in the scene before her farewell to her mother (which Park called heartbreaking), as well as the high sync rate with Son Ye-jin. Also, Jung An-ji of Sports Chosun
praised her for the historical accuracy of portraying the princess: citing she acted "perfectly" with the life of a girl during the Korean Empire. She had a recurring guest role in the hit fantasy drama Guardian: The Lonely and Great God''. Kim showed an overwhelming presence and increased
audience immersion in the early stage of the show, making a big impact as a
cameo.
2017–2020: Adult roles and career fluctuations In 2017, Kim participated in Korean dubbing for the character Mitsuha Miyamizu in the
anime drama film Your Name. She switched back to live-action and co-led the historical and political drama
The Emperor: Owner of the Mask with
Yoo Seung-ho, which premiered on 10 May. This marked her first adult historical drama after five years since
Moon Embracing the Sun. Despite its high ratings, the time of the drama's original run coincided with her slump period — Kim expressed how she made efforts to understand her character as a heroine. She felt lost and started losing confidence in herself as an actress. As everybody was praising her acting and visual, she felt embarrassed because she could not come to a full understanding of who her character was. Kim suffered with "growing pains" and "transition period" after seven months of filming
The Emperor: Owner of the Mask. She felt emptiness in her schedule and felt uncomfortable even though she was resting. She made a special appearance in drama
While You Were Sleeping to show her support for scriptwriter Park Hae-ryun, who she worked with on KBS's
Page Turner. In August 2017, she ended her contract with
SidusHQ after seven years. In December, Kim launched her one-person agency,
E&T Story Entertainment, in partnership with
LOEN Entertainment. The agency is currently led by Park Chan-woo, Kim's manager in her SidusHQ days. In 2018, Kim was cast in the romance drama
Radio Romance, which began airing on 29 January. She played a radio scriptwriter who isn't exactly talented in writing. On 24 January, a photo was shared on SNS saying that Kim was shooting underwater. The photo shows a woman wearing a hanbok in the water on 21 January. On this day, the lowest temperature was recorded below minus 16 degrees. During the press conference for the premiere of
Radio Romance held on 25 January, the PD addressed online criticism regarding the outdoor water filming, despite the weather warnings. He issued an apology stating that "Kim So Hyun's outdoor water filming wrapped up on Sunday [21 January]. We debated on it a lot since she would be getting in the water. We ensured safety equipment nearby and a camping car on set and finished filming in the shortest amount of time possible. Due to time constraints, an action stunt double filmed additional outdoor water scenes yesterday [24 January]. It was filmed by an action actor, not Kim So-hyun, wearing a winter suit and shot in a similar situation. The number of shots was done with one take and protection was taken right away. We apologize for causing concerns with this matter. The filming set is our lives. Naturally, safety is important." At the press conference, Kim's hand was visually seen red. On the same day, she co-hosted the 27th
Seoul Music Awards with
Kim Hee-chul and
Shin Dong-yup. After 10 years of debut, Kim hosted her own
travel reality show Because ''This is My First Twenty - Kim So-hyun's YOLO Solo California, where she challenged herself and discovered her true identity in a foreign country. On October, she was named as one of the first tenth generation hosts to host a survival reality show
Under Nineteen on MBC. Kim received positive feedback from viewers of the premiere for her strengths as a host, as noted by Korea Economic TV'' — audience engagement, her "steady" voice, charisma, as well as her styling, which the publication deemed "colorful". By early-2019, Kim, Kim Hee-chul and Shin Dong-yup were selected for two consecutive years as the hosts for the Seoul Music Awards, hosting the 28th ceremony. Kim played the lead role in
Netflix's original production
Love Alarm, based on the popular
webtoon of the same name. Kim explained her character is experiencing the emotion of love for the first time, and it reminded of herself. She decided to tap into those feelings as she wanted to portray a living and breathing character with Jo-jo. Kim Yoo-jin of
Exsports News said that Kim showed a high sync rate and a "rich and stable" acting performance in the series.
Forbes Joan MacDonald said that Kim fit well with the character Jojo. Further, the Netflix series was ranked the platform's 8th most loved work in South Korea in 2019. '' press conference in 2019 The same year, she was cast alongside
Jang Dong-yoon in a
romantic comedy drama set in the
Joseon period,
The Tale of Nokdu as a clumsy and hot-tempered
Kisaeng trainee.
Chon Kye-young and Hye Jin-yang, the author of both webtoons named Kim as their first choice in casting the leading woman. Shin Ji-won of
Hankyung said that Kim So-hyun's character was able to mesmerize the viewers because Kim blended well with her character. Jang Dong-yoon stated, "I was convinced that there would be no better actress to play Dong Joo other than So-hyun, I was very grateful to have met my best partner in her." The pair were donned the nickname "
Manhwa tearing" chemistry by the viewers for capturing everything from laughter to excitement and adding their colours to the original characters. Her role as Dong Joo earned her the Excellence Award at the year end
KBS Drama Awards. The series was the 10th most talked primetime Korean dramas aired in 2019. On 1 October, an official statement from
Kakao M revealed that Kim received 815 shares (about 100 million won) of it to resolve issue rights to strengthen solidarity with affiliates and entertainers. Kim is one of many Kakao M-affiliated artists who received stocks from the company, which, according to reports, is preparing to rejoin
Korea Exchange through a
re-IPO. On 29 October, Netflix confirmed that Kim would reprise her role as Kim Jo-jo in the second season of the drama series
Love Alarm. In 2020, Kim's travel reality show
Because This Is My First Twenty surpassed 6 million views as of May 2020 on
YouTube, Naver TV and
Facebook. On 15 January 2021, E&T Story Entertainment released an official statement stating that Kim would be leaving the agency. On 18 January, Kim signed an exclusive contract with the
Culture Depot.
2021–present: River Where the Moon Rises and Good Boy In February 2021, Kim starred as the alter-ego protagonists in the historical drama
River Where the Moon Rises which premiered on 15 February. She plays as a female general, who was born as a princess but raised as a general, and chases for her goal to straighten the ruined status of her country,
Goguryeo. She gained praises for her solid performance and sword skills, and her portrayal of three different characters; Assassin Yeom Ga-jin,
Princess Pyeonggang and the queen of Goguryeo Queen Yeon, for which she was nominated for a
Baeksang Arts Awards in
Best Actress - Television, becoming one of the category's youngest nominees. At the end of the year, Kim became the host of the
2021 KBS Drama Awards with
Sung Si-kyung and
Lee Do-hyun This is a return to hosting in 6 years since 2015. In 2022, Kim signed with Ieum Hashtag. In July 2023, she returned to the small screen with the
tvN romantic comedy series
My Lovely Liar, She also starred in the webtoon-based romantic comedy-drama ''
Serendipity's Embrace'' along with
Chae Jong-hyeop and directed by
Song Hyun-wook, where she played a woman who meets her first love again after ten years. In 2025, she starred opposite
Park Bo-gum in the
JTBC action-comedy television series
Good Boy directed by
Shim Na-yeon. ==Other activities==