2009–2014: Iris and rising overseas popularity
Back on the small screen in 2009, Kim played an NIS profiler in the spy action thriller Iris. It was one of the most expensive Korean dramas ever produced and was a critical and commercial success with an average viewership rating of 30%. Kim shed tears at the KBS Drama Awards when she won an Excellence Award in a Mid-length Drama; which was her first acting award, excluding newcomer and popularity awards.
Kim left her then-agency Namoo Actors in January 2010 to join Lua Entertainment, which was founded by her brother-in-law. That year, she also played a horse jockey who dreams of winning the championship in the sports film Grand Prix.
After the success of Iris, she again drew positive reviews in the romantic comedy series My Princess (2011); Kim played an ordinary college student who discovers that she is Korean royalty. Later that year, she starred in her first Japanese television drama Boku to Star no 99 Nichi, where her character is a Korean Wave star who meets an ordinary Japanese bodyguard and he somehow makes her fall head over heels in love with him. The Fuji TV drama, which aired in Japan from October to December 2011, raked in 9 to 10 percent of viewers' ratings on average, launching Kim as a household name in Japan. Kim later encountered backlash from some Japanese netizens for allegedly promoting South Korea's claim in the Liancourt Rocks dispute during her 2005 trip to Switzerland as a goodwill ambassador.
In 2013, Kim starred in her first historical drama Jang Ok-jung, Living by Love as the infamous royal concubine Hui-bin Jang. This was followed by another period role, as the wife of famed Chinese calligrapher Wang Xizhi in the Chinese television drama Saint Wang Xizhi.