After a stint as a fashion model, Yoo launched his acting career in 1998 then rose to fame through the films Attack the Gas Station (1999) and Ditto (2000).

In the succeeding years, he gained acting recognition by working with acclaimed directors such as Hur Jin-ho in One Fine Spring Day (2001), Park Chan-wook in Oldboy (2003), and Hong Sang-soo in Woman is the Future of Man (2004).

His sensitive and artistic image in this film and the warm character he displayed as a guest on TV talk shows helped to propel him to stardom.

In this early part of his career, he was known particularly for the wild colors that he would dye his hair (white in Attack the Gas Station, blue in Ditto, blonde in Libera Me).

Although it wasn't a big hit with audiences, his performance in this film opened many critics' eyes and drew widespread praise, while officially launching the second stage of his career.

[5] For the next two years, Yoo didn't appear in any new films, because Natural City took an unusually long time to progress from shooting to a commercial release.

He then appeared in three works in 2003: Natural City (which bombed, despite its big budget and special effects), the horror/suspense film Into the Mirror, and Park Chan-wook's acclaimed Oldboy.

As Yoo's career established itself he began to appear in many high-profile projects, such as in well-known arthouse director Hong Sang-soo's Woman is the Future of Man (which, like Oldboy, screened at Cannes in 2004);[6] Yim Pil-sung's big-budget Antarctic Journal, shot in New Zealand;[7] and the action/noir Running Wild with Kwon Sang-woo.

As soon as he finished shooting the 2007 period film Hwang Jin-yi about a Joseon-era gisaeng,[9] Yoo chose to act in the play Come to the Ghost House.

[16][17] After getting his master's degree in 2008 from Chung-Ang University's Graduate School of Advanced Imaging Science, Multimedia & Film, in recent years Yoo has focused more on his passion for directing.

[19] In addition to directing his fourth short film Invitation, Yoo wrote the script and plays the main character alongside leading lady Uhm Ji-won.

[27] Yoo said he plans to continue producing or directing movies based on strong social issues as he is interested in the plight of the less privileged.

[45] Yoo first met actress Kim Hyo-jin in 2003 when they were models for a clothing brand, and the two became friends after continuously meeting in photo shoots.

He joins charity photo shoots and auctions,[65][66] has helped set up a kindergarten in Nepal,[67] has donated to Haiti earthquake relief,[68] has donated funds for building schools in Myanmar, has joined a charity photo shoot to benefit victims of facial burns,[66] has volunteered in a campaign to deliver free lunches to underprivileged people,[69] has promoted the adoption of abandoned dogs, and has campaigned against domestic violence towards migrant wives.

[72] On March 8, 2022, Yoo donated 10 million won to the Hope Bridge Disaster Relief Association to help the victims of the massive wildfire that started in Uljin, Gyeongbuk and has spread to Samcheok, Gangwon.