On April 1st, 2012, a video teaser of MBC Music’s show Making The Star was released, which revealed that a new group under DSP Media (the agency which girl group KARA was in) was soon to be released. The group was formerly named DSP Boyz.
Soon, DSP Media’s YouTube account started to release more teasers of the show consecutively on April 4th, the third on April 9th, and the last on April 12th, 2012. The next day, on April 13th, 2012. the group was chosen to be the brand ambassador for the sports casual brand Spris.
On April 17th, 2012, the members’ identities of the group were revealed through DSP Media’s YouTube account. They revealed one member a day starting from Jaehyung on April 17th, Yunyoung on April 18th, Jihu/Hyojun on April 19th, Sungmin on April 20th, Seungyeop, and Dowoo/Hyeongkon on April 22nd, Seungjin on April 23rd, 2013.
On April 24th, the group’s name went from DSP Boyz to A-Jax. The name A-Jax is said to be the name of the mythological Greek hero that contributed to being the winner of the Trojan War.
The first video teaser of the group was released on May 7th, 2020, with the appearance of KARA member Goo Hara, who was also the group’s senior. Since there was a little information regarding the video teaser, the fans were mistaking it for KARA’s comeback teaser or Hara’s upcoming solo event. The misunderstanding then was cleared on May 10th, 2012, when it was revealed that it was regarding A-Jax’s debut.
The official full song and music video of the teaser was finally released on May 15th, 2012. The song name was revealed to be called “Never Let Go” and later stated that it was part of the prologue song (not their title track). Goo Hara was featured in the music video.
Later, the pre-debut A-Jax also made an appearance as the opening act in KARA’s last two shows of their first tour, Karasia, in Saitama, Japan.
At the concert, the members gave an enthusiast speech, “It’s an honor to be able to stand on such a big stage before our debut. It’ll be a learning experience for us. As it is a great opportunity, we’re going to work to show as much of our charm as possible.”
A-Jax officially made its debut on June 1st, 2012.
The first announcement of the group’s debut was revealed on May 1st, 2012, when it was revealed that A-Jax would be the first Korean idol group to debut within Korea and Japan simultaneously, following the group SS501’s footsteps. They signed with the label Universal Sigma (the same agency which handled Kara and Rainbow) to handle their Japanese activities.
A teaser of the music video for their official debut song “One 4 U” was released on May 28th, 2012, through the official YouTube account. The music video itself was praised for its CG effects and cost of $42,500 USD.
The music video and full single of “One 4 U” was released on May 31st, 2012, with the look and feel of Greek Gods.
They performed their debut song on MBC’s Show! Music Core on June 2nd, 2012, and used the song “Never Let Go” as their comeback intro opening.
The group also recorded the Japanese version of “One 4 U” on June 19th, 2020, and released it on August 8th, 2012.
In 2016, A-JAX was revealed to have undergone a slight line-up change as three A-Jax members (Jihu, Jaehyung, and Sungmin) left the group.
It was revealed that the reason was that the three members who left went to pursue a different path in music.
The announcement was released on the official A-JAX homepage by DSP Media representative:
“Ji Hoo would pursue acting, while Jaehyung and Sungmin would be doing the kind of music that they want to do. We will support them as they decide to go on their own paths towards their dreams. Since Jihu and Sungmin have started their own path, as their management agency, we will do all that we can to support them. Jae Hyung has decided to terminate his contract with the agency, we will also send him our support. Moreover, a new member Joonghee will be added to the group. From now on, A-Jax will be promoting as Hyeongkon, Yoonyoung, Seungyup, Seungjin, and Joonghee. Please do support the new A-JAX as well as Jihu, Sungmin, and Jaehyung since they will be going their new paths. We will not forget your love and care. We are going to do our best in the future to show great promotional activities for all of you.”
After new member Junghee joined the group in the same year, A-Jax began to promote as a five-member band.