Lee Se-young was first seen in the television drama series ‘The Brothers' River’ in 1997. She continued to star in television series like ‘The Path of the Great Dynasty’ (1998), ‘Did We Really Love?’ (1999), ‘Promise’ (1999), ‘Foolish Princes’ (2000), ‘I Want to See Your Face’ (2001), ‘Present’ (2002), ‘My Love Patzzi’ (2002), ‘Land of Wine’ (2003), ‘Drama City’ (2003), and ‘Dae Jang Geum’ (2003). Se-young went on to make her big-screen debut in the 2004 romance drama film ‘Dance with Solitude’ directed by Su-in Lee. That same year, she also starred as ‘Go Mi-nam’ in the South Korean comedy film ‘Lovely Rivals’ directed by Jang Kyu-sung. The film grossed over $4.7 million at the box office. In 2005, she became a part of the South Korean television drama ‘Sisters of the Sea’ written by Lee Hee-woo. The show aired its final episode in 2006. She was next seen in television series and shows such as ‘Kokkiri’ (2008), ‘Bachelor's Vegetable Store’ (2011), ‘Dream of the Emperor’ (2012), ‘Missing You’ (2012), ‘Goddess of Marriage’ (2013), and ‘Adolescence Medley’ (2013). In 2014, she starred as ‘So-hee’ in the South Korean teen romantic comedy film ‘Hot Young Bloods’ directed by Lee Yeon-woo. The film grossed over $10 million at the box office.
Se-young portrayed ‘Min Hyo-won’ in the 2016 South Korean television series ‘The Gentlemen of Wolgyesu Tailor Shop.’ She won the ‘Baeksang Arts Award’ and the ‘KBS Drama Award’ for her performance in the show. She was next seen in television series such as ‘Hit the Top’ (2017), ‘A Korean Odyssey’ (2017), ‘The Crowned Clown’ (2019), ‘Doctor John’ (2019), ‘Memorist’ (2020), and ‘Kairos’ (2020). Se-young became a recipient of the ‘MBC Drama Award’ for her portrayal of ‘Seong Deok-im’ 2021 South Korean television series ‘The Red Sleeve.’ The show aired 17 episodes before going off-air in 2022. Se-young will be next seen in the upcoming South Korean television series ‘The Law Cafe’ where she will portray ‘Kim Yu-ri.’