Kim gained praise for her versatility since she also portrayed Chae Shi-ra's childhood counterpart Hwangbo Soo in the period epic Empress Cheonchu, for which she learned how to ride a horse and shoot with a bow and arrow. 

Later that year, she joined the cast of romantic comedy series He Who Can't Marry, a remake of Japanese drama Kekkon Dekinai Otoko.

She landed her first leading role in the 2010 daily drama A Good Day for the Wind to Blow (also known as Happiness in the Wind), which further raised her Korean Wave profile.

She then starred in weekend drama A Thousand Kisses (2011-2012), which explored age differences in relationships.

In 2012, she starred in the ten-episode Chinese drama Secret Angel, which aired on the portal website Sohu.com.

She returned to Korean television in the cable drama Happy Ending.

That same year, she also appeared in Music and Lyrics, a reality show in which an actress and a male musician are paired together to collaborate, as lyricist and composer respectively, in creating a song. So-Eun and Lee Junho (from boyband 2PM) composed the song "Love is Sad," which Lee also recorded; it was released as a single and featured on the soundtrack of Feast of the Gods.

After playing Princess Sukhwi in the period epic Horse Doctor (also known as The King's Doctor, 2012-2013), Kim starred in After School: Lucky or Not (in the Korean title, bokbulbok refers to a game of chance, literally meaning "Luck, No Luck"), which was distributed via SK Telecom's online and mobile portals. Kim played a timid girl who gets invited to a high school club, and encounters fantastical "missions" every episode, which draws out her bright, lively personality.

She and Victoria Song (member of girl group f(x)) were also chosen to host Glitter, a variety show on the lives of trendy twenty-somethings.