Pre-debut Jun trained under
Jellyfish Entertainment alongside
VIXX before transferring to
CJ E&M. He appeared on
Mnet's
I Can See Your Voice as
Kangta's look-alike. Jiham competed on
Superstar K5 prior to becoming a trainee under CJ E&M, and later appeared on
I Can See Your Voice as well, winning the episode and earning high praise from
Got7's
JB. Wow trained at
YG Entertainment alongside
Winner Byeongkwan and Yuchan trained under
JYP Entertainment before joining Beat Interactive. A.C.E released their second single album
Callin' on October 19, 2017. In October 2018, all group members participated in the survival shows
The Unit and
Mix Nine. Jun and Chan competed on
The Unit, and Jiham, Wow, and Kim Byeong-kwan competed on
Mix Nine under their given names. Kim Byeong-kwan and Jiham won 4th and 8th place respectively on
Mix Nine in January 2018. They began preparations to debut in a temporary boy group, but the debut was cancelled later that year. Chan won 9th place on
The Unit in February 2018. He debuted with the temporary boy group
UNB on April 7, 2018, and they finished their promotions on January 27, 2019. On March 15, 2018, the group released a special single titled "5TAR (Incompletion)", with the song serving as a gift to fans after their brief hiatus to join
The Unit and
Mix Nine. On June 7, 2018, A.C.E released their first repackaged album
A.C.E Adventures in Wonderland with the title track "Take Me Higher". Chan did not take part in the album due to his promotions with
UNB. A.C.E featured on their first collaboration with French DJ Hcue for the track "I Feel So Lucky" released on September 14, 2018, aiming for a Moombahton sound fused with K-pop elements.
2019–2020: Under Cover, Under Cover : The Mad Squad, and HJZM : The Butterfly Phantasy , November 2019From left: Chan, Jiham, Jun, Kim Byeong-kwan, Wow On May 17, 2019, A.C.E released their second extended play
Under Cover with five songs, including a title track of the same name. A.C.E released their third extended play
Under Cover: The Mad Squad on October 29, 2019, containing six tracks with "Savage" serving as its lead single. A.C.E released their fourth extended play
HJZM: The Butterfly Phantasy on September 2, 2020, with the title track "Goblin (Favorite Boys)," along with four other songs. On December 18, 2020, A.C.E signed with Asian Agent for global management. A.C.E released a remix titled "Fav Boyz" on January 8, 2021, of their song "Goblin (Favorite Boys)" by American DJ
Steve Aoki, featuring the Nigerian-American rapper
Thutmose.
2021–2022: Added management agency, Siren: Dawn, Changer: Dear Eris, and military enlistments On February 5, 2021, it was announced that
Swing Entertainment would co-manage A.C.E alongside Beat Interactive. Swing Entertainment will be in charge of artist's domestic broadcasting appearances, while Beat Interactive is in charge of production, global marketing, artist care management and fan marketing. On April 16, 2021, A.C.E released the collaboration single "Down", featuring
Grey. A.C.E released their fifth five-track EP
Siren: Dawn on June 23, 2021, with the lead single "Higher". The EP was praised by
NME, which stated: "Keep an eye on this headstrong quintet, because there's no question they'll surprise us in the years to come." A.C.E released "Spark" as part of the original soundtrack for
boys' love Korean drama Light on Me on July 8, 2021. Their participation on the song showed support for the LGBTQ+ community. Leader Jun said of the release, "Just like how all of our fans, CHOICE, are different in their own special ways, we know that there [are] a range of different ways to love among all kinds of people in this world which we acknowledge and respect." A.C.E released their second repackaged album
Changer: Dear Eris on September 2, 2021, with the lead single "Changer". On August 20, 2021, it was announced that Wow would enlist for his
mandatory military service on September 10, 2021, as a public service worker. On September 23, 2021, Jiham enlisted for his military service as a public service worker. On February 7, 2022, Jun enlisted for his military service as an active duty soldier. On April 11, 2022, Kim Byeong-kwan enlisted for his military service as a member of
KATUSA, the second K-pop idol to do so after
Day6's
Young K. On August 16, 2022, Chan enlisted for his military service as an active duty soldier. On June 9, 2023, Wow was officially discharged from military service. On June 22, 2023, Jiham was discharged from military service, and on the 25th, he completed his first schedule with Wow after returning. On August 6, 2023, Jun was discharged from military service, and on the 8th, he completed his first schedule with Wow after returning. On October 13, 2023, Kim Byeong-kwan completed his first schedule after being discharged from military service. On February 15, 2024, Kang Yu-chan completed his first schedule after being discharged from military service.
2023–present: Returning projects following mandatory military service, My Girl: "My Choice" and "Supernatural" On August 12, 2023, Beat Interactive announced that members Jiham, Jun, and Chan would begin using their given names Lee Donghun, Park Junhee, and Kang Yuchan for promotion. Wow would be the only remaining member to use a stage name. On February of 2025, Donghun revealed he has changed his legal name to Jiham. On November 7, 2023, A.C.E released the first pre-release single "Effortless" for their sixth mini-album. On November 11, 2023, A.C.E held their first fan concert after their completion of their military service, titled
Overturn. Kang Yuchan did not perform at the concert due to his military service. They performed their newly released pre-release single "Effortless" as well as their then-upcoming pre-release single "Angel" for the first time. On November 16, 2023, A.C.E released the second pre-release single "Angel" for their 6th mini album.
My Girl: "My Choice" On February 22, 2024, A.C.E released their sixth mini album
My Girl: "My Choice" with the lead single "My Girl". Kang Yuchan did not take part in the album due to his military service. Their album release project, titled "PetFlix", included the opening of an official website designed with an
OTT site concept. The project also featured a 5-member busking event (including Yuchan, who returned from enlistment the day prior) on February 16 at
COEX Mall before the release. In April 2024, A.C.E held a fanmeeting "Home Sweet A.C.E" for the first time in 3 years in Korea. Later in April the band toured in Japan before releasing the special single "Supernatural" on May 31, 2024, as a full unit, marking member Kang Yuchan's first official release since his return from military enlistment. Supernatural gained popularity in the US giving A.C.E their first entry in the Top 100 Mainstream Top 40 Airplay chart, where it ranked 93rd by the 40 largest radio stations in the U.S. It also ranked 63rd in the Media Base Top 40 music chart following
BTS,
Blackpink,
NewJeans,
TXT, and
Monsta X. In June 2024, A.C.E toured the US with their "Rewind:US" tour covering 14 cities and performed at KCON in Los Angeles. In July 2024, A.C.E announced Latam and European dates for the "Rewind:US" tour. ==Members==