[7] She rose to fame after starring in 2004 hit historical drama Emperor of the Sea, which was exported to other Asian countries, South America and the Middle East, introducing Soo Ae to a wider international audience.

But she revamped that image in the 2007 romantic comedy Two Outs in the Ninth Inning opposite Lee Jung-jin, playing a 30-year-old foul-mouthed, disheveled and jaded single woman struggling with life and love.

"[2][10] After a successful big screen debut in A Family,[11] Soo Ae starred opposite Jung Jae-young in the comedy Wedding Campaign, and Lee Byung-hun in the melodrama Once in a Summer.

[12][13] In 2008, she was cast as the titular Sunny in a film about an ordinary housewife who becomes a "consolatory band" singer in order to search for her husband who has been dispatched to fight alongside American troops in the Vietnam War.

Director Lee Joon-ik sought to tell a war story from a female-centric point of view, saying the film deals with the meaning of love and humanitarian as it depicts a long voyage of self-discovery.

[18] Describing herself as "timid" and "too introverted," Soo Ae credits her co-star Cho Seung-woo for making it easier for her to fully absorb herself in the love aspect of her role, such that it felt "like [they] were actually in a relationship during the shoot.

She talked about the heightened fear she felt in a confined studio as her radio DJ character receives threatening phone calls from a kidnapper (played by Yoo Ji-tae), as well as the physical difficulty of filming chase and fight scenes in high heels.

[21] In her return to television, Soo Ae played a cold-blooded double agent in Athena: Goddess of War, undergoing martial arts training to perform her intense action scenes in the spy series.

[22] Then in the miniseries A Thousand Days' Promise by famed drama writer Kim Soo-hyun, Soo Ae impressed critics and audiences with her unsentimental portrayal of a woman who is slowly losing her memory due to Alzheimer's disease.

Soo Ae said she is attracted to roles with an oeyunaegang quality, which literally translates to "iron fist in a velvet glove," meaning those who appear gentle but are determined and strong.