1999–2009: Beginnings as a child actor Yoo made his entertainment debut in a cellphone commercial in 1999 after Yoo's mother sent in a photo of her son to an ad agency. He rose to stardom in his first film
The Way Home, playing a bratty city boy who learns to appreciate country life when he's forced to spend the summer with his deaf-mute grandmother. The low-budget film was a surprise box office hit in 2002, drawing more than 4 million admissions. He was then affectionately labeled as "
Nation's Little Brother". Thereafter, Yoo also starred in animal movie
Hearty Paws (2006) about a boy and his beloved dog, and
Unforgettable (2008) about school children from a remote island who go on a field trip to a candy factory in
Seoul during the 1970s. He continued acting in television, appearing in
Magic Warriors Mir & Gaon (2005), an adventure series for children. Yoo further built his filmography, playing younger counterparts of male protagonists in television dramas, including general
Yi Sun-sin in
Immortal Admiral Yi Sun-sin (2004),
King Seongjong in
The King and I (2007), and
Gwanggaeto the Great in
The Legend (2007). In 2009, Yoo starred in the action film
City of Fathers and thriller film
4th Period Mystery. He also played
Kim Chunchu in the period epic
Queen Seondeok.
2010–2014: Teen roles In his teens, Yoo was cast in one of the major roles in
Master of Study (2010), a Korean screen adaptation of Japanese
manga Dragon Zakura. He then played a more mature role in
Flames of Desire, as the second-generation son of a wealthy
chaebol family who is uninterested in the battles of succession among his relatives and becomes a married man at 21. Later that year, Yoo sang a duet with singer/actress
IU titled "I Believe in Love" for the charity program
Love Request. The song's lyrics was based on a diary that Yoo had written while seeing orphans of war in the slums of Sri Lanka. In 2011, Yoo trained in swordplay and martial arts in his role as an assassin in
Warrior Baek Dong-soo, an
action-period drama based on the
manhwa by Lee Jae-heon. He also voiced Greenie, Leafie's adopted son, on
Leafie, a Hen into the Wild, which was adapted from a bestselling children's novel by
Hwang Sun-mi. He then co-starred with
Kim Ha-neul in the
thriller Blind. In 2012, Yoo was cast in his first role as a leading man in
Operation Proposal, a Korean
remake of the
Japanese drama Proposal Daisakusen. This was followed by a supporting role as the
Jade Emperor, ruler of the heavens, in the fantasy-period drama
Arang and the Magistrate. Afterwards, he starred in the melodrama
Missing You, playing a cold man who hides a vengeance-filled heart behind his seemingly gentle smile. Known in the press as "Little
So Ji-sub" for his resemblance to the said actor, in 2013 Yoo starred in the music video for So's
single "Eraser" together with
Park Shin-hye. This was his second time promoting So's musical endeavors, after "Lonely Life" in 2008. Following that, Yoo's first photo book titled
Travel Letter, Spring Snow, And... was published; it was the last project shot by celebrity photographer Bori before her death on April 9, 2013.
2015–present: Adult roles and rising popularity As his first post-army project, Yoo appeared in the music video for
Naul's "You From the Same Time" in 2015. He was next cast as a stubborn
webcomic writer raising a cat in the TV adaptation of
webtoon Imaginary Cat. Yoo followed this by starring in the joseon-era romance film
The Magician directed by
Kim Dae-seung, in which he plays a circus magician who falls in love with a princess. Yoo was then cast in
SBS's legal thriller series
Remember as a lawyer with
hyperthymesia who defends his father on
death row. In 2016, Yoo starred in the historical comedy film
Seondal: The Man Who Sells the River as the titular character Kim Seon-dal. In 2017, he starred in
MBC's
historical melodrama The Emperor: Owner of the Mask and romantic-comedy ''
I'm Not a Robot''. In 2018, he was cast in SBS's high school drama
My Strange Hero. In 2020, Yoo starred in the mystery thriller
Memorist as a detective in the police force with the power to read people's memories. In 2021, Yoo played a passionate inspector in
KBS2 historical drama
Moonshine. In 2022, he made a special appearance in the
action crime film Special Delivery. In March 2022, Yoo signed with new agency
YG Entertainment. In 2023, Yoo returned to the small screen with his first streaming project,
Wavve's crime thriller
The Deal portraying a completely different character than his previous ones - a financially struggling young man who accidentally kidnaps his school friend for a 10 billion won ransom. The mini-series was the only Korean drama invited to the third edition of the
Red Sea International Film Festival in
Jeddah, Saudi Arabia. Yoo walked the red carpet at
VOX Cinemas in the
Red Sea Mall together with the director Lee Jung-gon and took part in the screening of the first three episodes of the drama. In 2024, he appeared in the music video for
Day6's "Welcome to the Show." In March 2025, Yoo signed with 333, a new management company established by
Son Ho-jun. ==Personal life==