Lee Si-young

Five Senses of Eros was an omnibus film from five different Directors, and in the segment "Believe in the Moment" three teenage couples decide to swap partners for 24 hours, played by Lee and her fellow up-and-coming actors Kim Dong-wook, Song Joong-ki, Shin Se-kyung, Jung Eui-chul and Lee Sung-min. In the comedy Descendants of Hong Gil-dong (also known as The Righteous Thief), Lee played the love interest of Lee Beom-soo, whose character is the 18th descendant of Hong Gil-dong, a Joseon-era Robin Hood whose family for generations has passed down the tradition of stealing only from the rich and giving to the poor while keeping their actions secret.

Lee played her first big screen leading role in the screwball romantic comedy Meet the In-Laws, which portrays the struggles of a comic book Writer (played by Song Sae-byeok) to tie the knot with his girlfriend (Lee) over the strong disapproval of their families, as they come from different regions with a long history of antagonism toward each other (the Korean title literally translates to "Dangerous Formal Greeting Between Families of the Bride and Bridegroom"). Deep-rooted regionalism which pits the southeastern Gyeongsang Province against the Jeolla Province in particular, had dogged various aspects of Korean society in the past, including the 1980s which is when the movie is set. Meet the In-Laws became the ninth top-grossing Korean film of 2011, with more than 2 million tickets sold.

She then headlined the horror film Killer Toon, playing a Writer of webcomics (called "webtoon" in Korea) who becomes the number one suspect after a series of murders are committed that mimic her famous comics. Co-starring Um Ki-joon as the detective on the case, the movie overlaps crime scenes with CG animation. In an interview, Lee said she picks roles if she is drawn to and can empathize with the character. Killer Toon attracted more than 1 million viewers, only the third Korean horror film to do so after A Tale of Two Sisters (2003) and Death Bell (2008).

Lee made her acting debut in 2008 in a guest appearance on season 3 of the TV procedural Urban Legends Deja Vu, followed by the historical drama The Kingdom of The Winds.

Lee never formally debuted as a singer, but she has made contributions to several of her films' soundtracks. She was also featured in one track on then-boyfriend Jun Jin's EP Fascination in 2009. And after she sang two tracks on Honey Family's fifth album Resurrection in 2010, band member Park Myung-ho praised Lee for her vocal talent.

To the surprise of fans and experts alike, Lee entered and won the 7th Annual Women's Amateur Boxing Competition in 2010, and the women's 50-kg category in the 10th KBI National Lifestyle Athletics Boxing Championship in November of that same year.

Her momentum continued throughout 2011, winning the women's 48-kg category in the 47th Seoul Amateur Boxing Match in February, and by RSC (Referee Stopped Contest) in the 7th National Amateur Boxing Championships in March. Lee Seung-bae, head coach of the Korean national boxing team, said Lee "has a very accurate left punch. She is tall and has long arms, a very good body for boxing," while coach Baek Seung-won said she has "the fire and the perfect physique" to become a professional boxer, but added, "She is a bit old (to turn pro now)." She later won the rookie of the year award for Seoul-based boxers.

In December 2012, she tried out for the first time for the national women's boxing team by competing in the under-48 kg light flyweight category in the National Amateur Boxing Championships, which doubled as the 2013 first national qualifying round. The 28-year-old was the oldest participant at the national championships with a 17 to 34 age limit. But Lee was defeated in the final of the 66th National Amateur Boxing Championships.

On April 24, 2013, Lee won the women's 48-kg title at the 24th National Amateur Boxing Championships in a controversial 22-20 decision, making her the country's first mainstream entertainer/celebrity, male or female, to become a national team athlete for any sport.

Lee said that her dream was to represent the country at the 2014 Asian Games, and her ultimate goal to win a medal there. Since her weight class is not included in international competitions such as the Asiad and the Olympics, she upgraded to the heavier under-51 kg class. But Lee was unable to participate in the Asian Games when she failed to enter the March 2014 final tryouts (as well as the two previous ones). Kim Won-chan, manager of the Incheon City boxing team, said, "She didn't have enough time to build up her skills for the bout. But we will keep working on her conditioning with the aim of getting her into the 2014 AIBA Women's World Boxing Championships on Jeju Island."

On July 1, 2015, Lee and her then agency J,Wide-Company filed a cyber defamation lawsuit against a reporter who allegedly spread rumors online that Lee had appeared in a sex video which the agency was using to blackmail her, leading to a suicide attempt; Lee and J,Wide-Company denied those rumors and an arrest warrant for the reporter was later issued by the Seoul Central Prosecutors' Office.

In April 2016, She examine a new movie named " Oh new wol ". this movie is a similar work alike "Ah jeo si".

In March, 2017, Lee was confirmed to star in MBC's action thriller Drama Lookout alongside Kim Young-kwang.

On July 2017, she announced through her social media that she is getting married on September and is 14 weeks pregnant.She gave birth to the couple's first child, a boy on 7 January 2018.