The eight members were introduced individually through teaser photos from July 16 to 23 (in order: Seolhyun, Choa, Hyejeong, Chanmi, Yuna, Mina, Jimin, & Youkyoung). AOA was revealed to be a dance group, with some members also playing instruments. Explaining the concept of their debut, FNC revealed that seven members are "full angels": Seolhyunari (Seolhyun), Choaya (Choa), Hyejeong.Linus (Hyejeong), Chanmi Titi (Chanmi), Yunaria (Yuna), Minaring (Mina), and leader Jiminel (Jimin), while Youkyoung (or "Y") is listed as a "half-angel/half-mortal"as she is only a member when the group promotes as a band. This is why AOA call themselves a "7+1" group. "Angel's Story" was leaked on July 28, two days before the official release. The music video for the title track "Elvis" was released on July 30. AOA had their debut stage on August 9 on M! Countdown and then Music Bank on August 10.
FNC confirmed that the group would be making a comeback with a second single album "Wanna Be" on October 10, the album cover was released along with the announcement; the album cover depicted the eight members as different fictional characters. Hyejeong, Jimin, Choa, Yuna, Chanmi, Mina, Seolhyun and Youkyung dressed as characters from Kill Bill, Léon, Legally Blonde, Tomb Raider, Harry Potter, Breakfast at Tiffany's, Romeo and Juliet, and The Fifth Element respectively. It was confirmed that five-member band unit, AOA Black would perform a stage in the first week of promotions for "Get Out". AOA Black made their first comeback appearance on the October 10 broadcast of KM's Music Triangle and performed the band version of "Get Out" for the first time. The band made their second appearance on the October 12 broadcast of Music Bank.
On July 11, it was announced that the band sub-unit, AOA Black (which consists of Jimin, Choa, Yuna, Youkyung, and Mina) would be making a comeback with their third single album with the title song "MOYA". The third single album and "MOYA" music video were released on July 26 and AOA Black had their first comeback stage on KBS Music Bank on the same day.
On October 9, the music video for "Confused" was released. The full album, Red Motion, was released on October 13, along with an "eye contact version" dance practice clip.
On January 16, AOA came back with another sexy concept and released their fifth single album (along with a music video) entitled "Miniskirt", it was produced by Brave Brothers, ElephantKingdom and Galactika. On February 9, AOA celebrated their first music show win on Inkigayo with "Miniskirt".
AOA released their title song, "Short Hair" in their first mini album on June 19. The album ranked No. 1 on different charts and also topped the M!Countdown chart in July. "Short Hair" the music video for "Short Hair" ranked eighth on Billboard's "Most Viewed K-pop Videos Around the World" for June. AOA performed the Girls' Generation song "Mr.Mr." with groups BESTie and Girl's Day for the "Half-Year Special" Edition of Music Bank on June 27.
On November 11, 2014, the group released their second mini-album, Like a Cat. On November 19, AOA had their second win on Show Champion with title song "Like A Cat".
AOA released a Japanese version of Like a Cat on February 25, 2015; the single also came with the Japanese versions of "Elvis" and "Just the Two of Us". On February 2, FNC released the short version music video of "Like a Cat", and it ranked No. 1 on Gayp! views daily and weekly ranking. Like a Cat ranked #6 on Oricon Daily Chart and ranked #1 on Tower Records Shibuya on the first day of its release; it also ranked No. 3 as their peak on Oricon Daily Chart.
AOA's first reality show "Open Up! AOA" premiered on February 26 on portal site Naver. The series consisted of 10 episodes, each 10 minutes long, and aired every Thursday. All eight members, including drummer Youkyung, were on the program. AOA started filming their new variety show with MBC Music called AOA One Fine Day in Nanwan Monkey Island, Hainan, China on April 7, 2015. 'One Fine Day' started broadcasting on June 13, 2015.
On June 2, 2015 AOA confirmed their comeback for mid-June entitled "Heart Attack" and their comeback showcase was held on June 22, 2015 at AX-Hall Seoul.
In August 2015, the group made their first appearances in the United States performing at KCON 2015 in Los Angeles on August 2 and New York on August 8. In the same month, it was revealed that AOA would make a comeback in Japan with a full-length album, being the first full-length album for AOA to release, featuring 8 of their previous Japanese singles and 3 new songs, including the title track,"Oh Boy". This album was later released on October 14, 2015.
Seolhyun was chosen to host the 2015 KBS Entertainment Awards alongside comedian Shin Dong-yup and singer Sung Si-kyung.
On January 1, it was announced that AOA would be having a comeback in the first half of the year, and that AOA Black would also be releasing new music.
On January 27, FNC said in interview that "Chanmi, Hyejeong and Yuna will promote as a unit group. They are planned to release a new song in February. We ask for a lot of anticipation." On the January 31. they announced that the new sub-unit was called AOA Cream and that they would make their debut on 12 February. On the next day they released the teasers on their official page. The title track "I'm Jelly Baby" was composed by Black Eyed Pilseung.
On March 3, Jimin made her solo debut with Call You Bae, featuring EXO's Xiumin.
In April 12, AOA hosted their own reality show,“OnStyle Live” – "Channel AOA”. “OnStyle Live” is a series that features stars hosting their own live shows, the shows are broadcast live and then repeated the next day.
FNC Entertainment announced on the 1st of May that AOA would release their 4th mini-album Good Luck on the 16th of the same month.
On August 8th and 9th, AOA members – including Youkyung – posted 9 tiles combination pic of their message to Elvis, name of AOA fans, on a piece of paper on their respective Instagram account to celebrate their 4th Anniversary. They also surprised their fans by releasing a making film of "Cherry Pop."
On October 15, 2016, it was announced that Youkyung had left the agency and group following the end of her contract, but would be a guest member in any future AOA Black activities. Soon afterwards Jimin posted a photo of all eight members on Instagram with the caption simply reading "AOA".
On November 29, 2016, FNC Entertainment officially announced that AOA was preparing for their first studio album comeback during the winter. Jimin later told Elvis to look forward to it since it would include a song for them.
AOA released their first Korean studio album titled Angel's Knock on January 2, 2017 through digital and physical platforms, which came more than four years after the group's debut back in July 2012. Various teasers were revealed from December 21, 2016 to January 1, 2017 through a special web page designed for the group and various social media networks.Park Choa (박초아)
Shin Jimin (신지민)
Seo Yuna (서유나)
Shin Hyejeong (신혜정)
Kwon Mina (권민아)
Kim Seolhyun (김설현)
Kim Chanmi (김찬미)
Former memberSeo Youkyung (서유경)
Unit breakdownAOA (main promotion unit): Jimin, Choa, Yuna, Hyejeong, Mina, Seolhyun, Chanmi
AOA Black (sub-unit): Jimin (guitar), Choa (guitar), Yuna (keyboard), Mina (bass), Youkyung (drums)
AOA White (non-promotional sub-unit): Hyejeong, Seolhyun, Chanmi
AOA Cream (sub-unit): Yuna, Hyejeong, Chanmi
2015 AOA Heart Attack Tour (October 4, 10 & 11, 2015)
AOA 1st Concert in Japan: Angels World 2015 ~Oh Boy Academy~ (December 18, 2015)
AOA Mini Live: Good Luck to Elvis (June 11, 2016)
AOA Summer Concert in Japan: Angels World 2016 (July 1 & 3, 2016)
2017 AOA 1st Concert [Ace of Angels] in Seoul (March 11, 2017)
AOA Heart Attack Comeback Showcase "League of AOA" (June 22, 2015)
AOA "Good Luck" Lucky Guard Showcase (May 16, 2016)
AOA has received eight music and entertainment awards and ten music program awards. On February 9, 2014, they received their first number-one win on South Korean music program Inkigayo with the song "Miniskirt".