2018–present: International acclaim and activism
In 2018, Yoo starred in Lee Chang-dong's film Burning opposite Steven Yeun, portraying a pure and sensitive young man, Jong-su, who tries to solve the mystery surrounding the woman he loves. Lee said the reason he cast Yoo, "Yoo Ah-in is one of the most famous Korean actors in that age group, and he's known for being good at delivering emotionally charged performances. In contrast to that, Jong-su is such a passive and shy character who doesn't show his emotions and who doesn't react, so I thought that would be really interesting for this actor to play this role." Lee then praised, "No one else could inhabit the character of Jong-su like he did. Yoo Ah-in is irreplaceable for this role, he is capable of conveying great nuance and sensitivity."
Burning had its premiere at the Cannes Film Festival, where Yoo walked the red carpet. It was selected as the South Korean entry for the Best Foreign Language Film at the 91st Academy Awards, became the first Korean film to make it to the final nine-film shortlist of the Academy Award for Best Foreign Language Film.
Yoo's performance was praised. Justin Chang of Los Angeles Times said on NPR, "As the movie's inarticulate male lead, Yoo Ah-in has, in some ways, the trickiest task. But he reaches almost subterranean depths of feeling." Jessica Kiang of The Playlist wrote, "Yoo's Jong-su is the very definition of still waters that run deep and dark and conceal who knows what in their murky reaches. Only a flawlessly assured performance could make the film's devastating yet ambivalent and enigmatic finale work as well as it does here." Pierce Conran of Screen Anarchy wrote, "Even more impressive is Yoo Ah-in, who is most well known in the West for playing the slimy son of a corporate head who serves as the villain in Ryoo Seung-wan's Veteran. Never better, Yoo embodies a sense of confusion, which eventually turns to dread in a performance that doesn't allow us to make any easy judgments about his character. Jong-soo's intentions throughout the story may seem innocent, but coupled with references to emasculation and his timid physicality, Yoo crafts an unusually compelling lead." Tim Grierson of Screen Daily wrote, "Ah-in Yoo is remarkable as Burning's ineffectual, withdrawn protagonist: he's the perfect vessel for Lee's grand treatise on the immutable fact that none of us truly understands anyone or anything." For his role in Burning, The New York Times featured Yoo in their list of "The Best Actors of 2018", making him the only Asian to be on the list and the first Korean actor to do so.
In November 2018, Yoo starred in the crisis film Default, taking over the role of Yoon Jeong-hak, who bet on the crisis after leaving the securities company and forecasting national bankruptcy. This character gave the impression that "is different from the youth that Yoo Ah-in has represented before", as in, "a person who represents the desire of ordinary people" and "a person who embraces the crossroads of the older and younger generations three-dimensionally." Yoo said he wanted to be "a medium to understand two generations at the same times", and he starred in the film with the thoughts of "how to accept the established system" and "what era we're living in right now." He also said the reasons he participated in this movie were because the movie dealt with the story in "a polite approach", and it was interesting that a female character deals with the country's major crisis and tries to solve it. In response, co-star Kim Hye-soo described Yoo as "an actor who has healthy mind", and thanked him for his decision to appear in the movie, saying that understanding message of the film and starring in this film is a possible choice because he is Yoo Ah-in.
Yoo was featured in Forbes as a star to take note of in January 2019. He next became the host, co-writer and co-producer for 12 episodes of KBS1 special talk show Do-ol Ah-in Going All Directions with philosopher Do-ol Kim Yong-ok, broadcast from January 5 to March 23, 2019. His first take on hosting a talk show garnered positive press reviews, noting, "he is the only actor who ever tried creating such a platform of communication", "honestly expressing his beliefs on various topics including gender discrimination", "[h]e met the audience directly with refreshing candor", and "Yoo Ah-in's and Do-ol's open communication method helped narrowing the generation gap." On April 3, 2019, Yoo and Do-ol were invited to participate in the 71st anniversary of Jeju uprising on Jeju Island, reading the declaration of peace and "The 71st Jeju Resolutions" in front of more than ten thousand spectators. Yoo said in his speech, "I shamefully did not know much about Jeju 4.3. I did not know what to call it, nor why we were not supposed to know about it [...] After learning about Jeju 4.3, I realized that it's a moment in history we all should never forget, and that we must continue to talk about and to make the issue current." And, "I could not imagine how the perpetrators could continue to go on with their lives after what they did. I would never have imagined how the victims and the bereaved families endure the years of grief, and how Jeju island bears these unbelievable wounds in its history."
In 2020, Yoo starred in a zombie thriller #Alive as survivor Jun-woo, based on the original script of Hollywood screenwriter Matt Naylor. The film premiered on June 24, 2020, and became the first film to surpass 1 million admissions since February 2020 prior to the outbreak of COVID-19 in South Korea. In September 2020, #Alive became the first Korean film to top Netflix Movies Worldwide chart. By the end of 2020, it became one of the most popular titles globally on Netflix.
In October 2020, Yoo starred in low-budget indie film Voice of Silence as a mutism character without a single line throughout the film, directed and written by a new female director Hong Eui-jeong, based on her script which was selected as one of the top 12 projects at Venice Biennale College-Cinema 2016/2017. Director Hong Eui-jeong said about the casting, "It was not easy to carry on a hardly commercial, small film, but I sent the script to Yoo Ah-in's agent and I was shocked that he responded sooner than I expected." For his role as a mute clean-up worker Tae-in, Yoo gained over 33 pounds (15 kg) and shaved his head. Hong Eui-jeong said that the original character in the script was supposed to be a slender young man, but in their first meeting, Yoo already gained weight because he thought it would suit with the character who worked a lot of physical labor. She recalled she was visually overwhelmed by his appearance, saying, "I didn't recognize him at first." After some discussions, she agreed that his physical transformation would work well with the silent Tae-in who used the body language to communicate. Later, she sent Yoo a video clip of gorrillas for his character study. She said, "I gave him a gorilla video because I set out Tae-in behavioral much more than I did emotional descriptions." Hong said the reason he cast Yoo, "Yoo Ah-in clearly had this boyish image that Tae-in needed. [...] He is not only excellent in acting, but he also has an image that creates time and space around the narrative. Thanks to him, Voice of Silence could have a more daydream-like fantasy atmosphere, and though I had worries about having a character without lines, his distinctive texture filled up the movie, leaving no void, despite the absence of lines". She praised him on his contribution to the character, saying, "Yoo Ah-in's interpretation of Tae-in's character was new and vivid beyond the script's suggestion. [...] [t]hrough his ideas and suggestions, I had the experience of discovering and learning about aspects of Tae-in, a character whom I created in the screenplay, that were till then unknown to me. [...] Ultimately, Tae-in was born with a look that was different from the feel in the scriptwriting stage".
Yoo's performance was critically acclaimed. Jennie Kermode from Eye of Film wrote, "With a greater focus on character than plot, the film benefits from solid acting all round [...] It's Yoo, however, who is the standout, taking his character through a remarkable arc." Nikki Baughan of Screen International wrote in his Fantasia International Film Festival review, "Working without dialogue, Yoo Ah-in resists the easy temptation of extreme physical expression; instead, he deploys restraint in his movements, conveying Tae-in's soul-destroying lack of options in his hangdog expression, his downcast eyes, his frantic attempts to cover up bloodstains in the dust." Nick Allen of Roger Ebert was similarly positive, saying, "Yoo Ah-in of #Alive giving a compelling, full-bodied performance." Jack Cameron wrote for The Film Magazine, "Yoo Ah-in, who was so excellent in Burning, is just as strong here, communicating everything with his highly expressive body language and his deliberately passive facial expressions. His breathing and grunting noises often hold your attention more strongly than some of the written dialogue".
For his roles in both #Alive and Voice of Silence, Yoo was named "Actor of the Year" at the 2020 Cine 21 Awards. For his performance in Voice of Silence, he won Best Leading Actor and Popular Star awards at the 41st Blue Dragon Film Awards, and became the second actor to win best actor award twice before the age of 40, following Sul Kyung-gu. He also won Best Actor in the Film Category at the 57th Baeksang Arts Awards, Cheval Noir Award for Best Actor at the 25th Fantasia International Film Festival, and Best Actor awards at the 30th Buil Film Awards and 15th Asian Film Awards respectively in 2021 for his performance in Voice of Silence.
Yoo's next role was that of the cult leader Jung Jin-soo in Yeon Sang-ho's Netflix series Hellbound that was released in November 2021. The series had its world premiere at the 2021 Toronto International Film Festival in the Primetime program of TV series in September 2021, and became the first Korean drama to make it to the festival. It was also screened at 26th Busan International Film Festival in newly created On Screen section, and at the 65th BFI London Film Festival in Thrill section in October 2021. Hellbound became the first Korean series to top Netflix TV Shows Worldwide chart within a day after its release, and topped Netflix's official weekly chart for non-English TV programs. Yoo gained recognition from critics and viewers for his performance, despite him being antagonist. Nick Allen wrote for Roger Ebert, "Yoo Ah-in is excellent in this role that has him delivering cryptic words of faith with a certain deadness in his eyes." Andrew Murray from The Upcoming wrote, "[...] it's Ah-in who steals the spotlight as soft-spoken cult leader Jeong Jin-Soo. Skilfully walking the line between menacing and charming, this charismatic figure has everything needed to become a memorable antagonist." Brian Tallerico of The Playlist was similarly positive and wrote, "Yoo Ah-in, also in the Netflix hit #Alive, is such a fascinating young actor, one who really gets what Hellbound should be about, that the show suffers when he leaves it". Polygon's Zosha Millman wrote, "Yoo Ah-in is particularly inspired casting, letting his chairman be just as virtuous as he is shifty, immovable in his low-key fanaticism. It's on his shoulders that the rest of the players can build their respective roles without ever feeling simply drawn". Hidzir Junaini from NME wrote, "His quiet demeanor belying an unsettling intensity, Yoo Ah-in's performance as the show's pivotal villain is creepily fascinating".
In 2022, Yoo portrayed the "Sanggye-dong Supreme Team" leader in a Netflix crime comedy film Seoul Vibe with Kim Sung-kyun, Jung Woong-in and Moon So-ri among the cast. Despite the film's mixed reviews, Yoo's performance received critical acclaim. Divya Malladi from Digital Mafia Talkies wrote, "Yoo Ah In as Dong Wook brought such a degree of believability to his character, with his blind courage that was balanced by a shrewd calculative nature." Pramit Chatterjee wrote for High On Films, "Yoo Ah-in is undoubtedly the star here, and he delivers a major chunk of the fireworks."
Yoo next will star opposite Lee Byung-hun, portraying South Korean professional Go player Lee Chang-ho in The Match. The film is scheduled to be released on Netflix in 2023. He will also play unemployed man with superpowers in Kang Hyeong-cheol's fantasy film Hi-Five, alongside Ra Mi-ran, and star in Netflix apocalyptic drama Goodbye Earth, a work based on the novel The Fool of the End by Kōtarō Isaka, directed by Kim Jin-min.
