AKMU (/ɑːŋmjuː/; Korean: 악뮤), formerly Akdong Musician (/ɑːŋdɒŋ mjuːˈzɪʃn/; Korean: 악동뮤지션), is a South Korean duo consisting of siblings Lee Chan-hyuk and Lee Su-hyun signed to YG Entertainment. As prominent figures of South Korea, their musical impact in their native country has earned them numerous accolades and the honorific title "The Nation's Siblings". They are also cited as "musical prodigies" and "geniuses".

Propelled to national stardom through the second installation of K-pop Star (2012–2013), AKMU officially debuted in April 2014 with Play, a studio album solely crafted by Lee Chan-hyuk alone. It topped the Gaon Album Chart, became their first entry on Billboard, namely the Heatseekers Albums Chart and the World Albums Chart, and birthed the three titular singles, "200%", "Give Love", and "Melted". It was well received by the public and critics, having sold more than 6.9 million downloads, and was awarded Best Pop Album in the 12th Korean Music Awards. Following the release of their critically acclaimed Puberty series, consisting of Spring (2016) and Winter (2017), the sibling duo reached greater career heights with Sailing (2019) and its lead single "How Can I Love the Heartbreak, You're the One I Love", which not only topped the Circle Digital Chart, but also sold 2.5 million digital copies, following "Last Goodbye" (2017), and was the fourth single to be certified triple platinum for streaming in Korea Music Content Association history.

Lee Chan-hyuk (born September 12, 1996) and Lee Su-hyun (born May 4, 1999) lived with their missionary parents in Mongolia for five years before returning to South Korea to pursue a career in music. Living an impoverished life, they were home-schooled, unable to afford education; detesting the idea of studying, they turned to music out of sheer boredom, learning to play the guitar and piano, respectively. Lee Su-hyun, the younger sister, abruptly returned to Korea for a short stay to resolve visa problems; her brother soon followed, deciding to stay. The siblings, under the name Akdong Musician, joined Proteurment, an intercollegiate association that supports amateur artists, after they were discovered on YouTube, and performed on stages with an original song titled "Galaxy".^{[unreliable source?]}

In August 2012, the duo participated in the preliminary auditions of K-pop Star 2 (2012–2013) at Jamsil Arena in Seoul. Eligible to perform in the first round, they sang a cover of Miss A's "Breathe" and an original song titled "Don't Cross Your Legs", an instant audience favorite. Amidst the panel of judges, Park Jin-young praised the chemistry between the siblings and the techniques they had incorporated in their performances; BoA praised the lyrics of their original song; Yang Hyun-suk described them as "true artists". Crowned as the winners of the competition, Akdong Musician received a cash prize of ₩300 million ($260,000), a Renault Samsung sedan, and the freedom to sign a contract with one of the three largest entertainment agencies in the country: S.M. Entertainment, YG Entertainment, or JYP Entertainment. Following almost two months of contemplation, the siblings signed an exclusive contract with YG Entertainment, believing it was the best place to support their music. Its founder, Yang Hyun-suk, cited the label would not change their unique image or their music style. The duo have since garnered a significant following, where songs performed on the show, namely "Don't Cross Your Legs," spawned to number two on the Gaon Digital Chart in December 2012. "You Are Attractive" topped the charts weeks after, beating the dominance of Christmas carols, and further compositions such as "A Foreigner's Confession", "Crescendo", and "It is Ramen", also displayed its reach. In the two months they were unafflicated, the duo filmed for commercials and released several singles, including "I Love You" for tvN drama All About My Romance (2013).

Akdong Musician debuted with the studio album Play on April 7, 2014, twelve months after winning K-pop Star 2 (2012–2013). It was promoted through three titular singles: "200%", selected by Yang Hyun-suk; "Melted", chosen by the duo; and the third, decided by the public through the reflected chart performance of the other songs. "Give Love" achieved the highest popularity, peaking at number four and three on the Gaon Digital Chart and the Billboard K-pop Hot 100, respectively, becoming the third single. "200%" charted atop the aforementioned charts for two weeks, while "Melted" peaked at number five and eight, respectively. Both lead singles appeared on the US World Digital Songs Chart at number 5 and 21, respectively, their first entries on the chart. Entirely written and produced by Lee Chan-hyuk, Play claimed number one on the Gaon Album Chart, number two on the US World Albums Chart, and number twenty on Billboard's Heatseekers Albums Chart, nearing a Billboard 200 entry, an uncommon achievement for a new K-pop act. Following the Sewol Ferry Incident, all of the sibling's activities were cancelled to share a state of mourning. The duo dedicated their single, "200%", to the victims of the sunken Sewol ferry and their families, and honored its victims by inserting an image of a yellow ribbon in the music video of "Give Love", released on May 2, 2014. Initially created for their debut album, the acoustic-ballad, "Time and Fallen Leaves" (시간과 낙엽), was held back for the autumn season. Released on October 10, the digital single peaked atop the Gaon Digital Chart in its second week of release, the latest addition of autumnal hits in the country; the single was not accompanied by a music video so the listeners would imagine their own stories. In November 2014, the duo embarked on a nationwide tour commenced in Seoul, titled "AKMU Camp".

Two years since their last album, Akdong Musician returned with their first EP titled Spring on May 4, 2016, the first record of the two-part series, Puberty. It was promoted with two lead singles: "Re-Bye" and "How People Move" (사람들이 움직이는 게), and represented the duo "growing up" through the themes of adolescence, where all six tracks are about their youth during their five-years in Mongolia. It caught the attention of domestic and international listeners alike; every song charted in the top ten of Korean and foreign music charts, including the Gaon Digital Chart, with "Re-Bye" becoming a chart-topper. Billboard named Spring the fourth best K-pop album of the year, where the record "boast a more theatrical feel to them to show the young duo is growing an exciting pace." To promote the EP, the duo performed at Seoul Forest on Children's Day in front of 10,000 people and 100,000 live streamers via V Live, simultaneously. and toured in Asia, holding showcases at Taipei, Singapore, Kuala Lumpur, and Shanghai. On New Year's Day, they released the short film "Spring of Winter", correlating to their second seasonally themed album, Winter (2017). In the film, playing themselves, they argue and disband Akdong Musician, while songs from the new album acted as its soundtrack. Two days later, the duo released their second studio album, the second in a conceptual two-part album series Puberty. Its lead single, "Last Goodbye" (오랜 날 오랜 밤) became the second best-selling song within the first half the year, and the fourth within the entire year. It also became one of twelve songs to surpass 100 million streams in 2017, and was awarded Song of the Year (January) at the 7th Gaon Chart Music Awards and the Digital Bonsang at the 31st Golden Disc Awards. Its second lead single, "Reality" (리얼리티), was chosen by the viewers of My Little Television's live broadcast. The duo began a tour titled "AKMU Diary", holding concerts in seven cities nationwide, including eight sold-out shows in Seoul from March 23. Originally planned for six shows, two more shows were added due to the positive response of fans.

Marking their first experimentation in music with EDM, a challenge initiated to breakfree from the duo's usual acoustic mould, they released their first single album titled Summer Episode, on July 20, 2017, fronted by the lead singles "Dinosaur" and "My Darling". Based on the siblings' childhood, the former single peaked at number six on the Gaon Digital Chart, number nine on the US World Digital Song Sales Chart, and received greater attention in the following years, re-entering charts six years after its release. Summer Episode served as the duo's last release ahead of Lee Chan-hyuk's mandatory military enlistment with the Republic of Korea Marine Corps on September 18. Voluntarily enlisted early in comparison to other K-pop celebrities, he entered a training center in Pohang, North Gyeongsang Province. In this time, he wrote most of Sailing (2019) while living on a ship over two years during his enlistment, as he was inspired by the new experience. The 22-year-old fulfilled his mandatory military service with the Marine Corps and was discharged on May 29, 2019, thus also simultaneously resuming the activities of Akdong Musician.

After a two-year hiatus from the industry, the newly-renamed AKMU decided to permanently use the abridged version of the name, Akdong Musician, referencing a "mischievous child", to avoid feeling constrained in their musical pursuits by its meaning. The duo returned with their third studio album, Sailing, on September 25, 2019, supported by the lead single "How Can I Love the Heartbreak, You're the One I Love" (어떻게 이별까지 사랑하겠어, 널 사랑하는 거지), a song they had originally performed at the 2017 Someday Festival. The lead single topped the Gaon Digital Chart for the month of October, remained atop their country's largest streaming platform for over a month, the longest period since the chart's creation, and stayed within its top ten for one year and two months after its release. It sold 2.5 million copies, receiving a platinum certification for download from the Korea Music Content Association (KMCA), and was certified triple platinum for streaming. The song further won Artist of the Year (September) at the 9th Gaon Chart Music Awards and the Digital Bonsang at the 34th Golden Disc Awards. Notably, the album marked Su-hyun's first credited contribution to an AKMU song, "Farewell" (작별 인사), which she arranged. To commemorate the launch of Sailing, AKMU held a guerilla stage at Yeouido Hangang Park on September 29; it gathered over 30,000 people, 7-8 times larger than the size of the venue. Released on November 16, 2020, the digital single "Happening" expanded on the themes of their previous single and stylistically acted as a bridge to AKMU's next studio album.