After being discovered through the Japanese video sharing website Niconico, Aoi made her major debut in 2011 with the release of her first single "Memoria",[3] whose title track was used as the first ending theme to the 2011 anime television series Fate/Zero.

In October 2016, following prolonged bouts of poor health, she announced an indefinite hiatus from musical activities following a two-day concert at the Nippon Budokan in November 2016.

[2][13] Aoi made her major debut under SME Records with the release of the single "Memoria" on October 19, 2011, the title track of which was used as the first ending theme song to the 2011 anime series Fate/Zero.

[14] Her second single "Aurora", which was released on September 5, 2012, is used as the fourth opening theme song to the 2011 anime series Mobile Suit Gundam AGE.

Her sixth single, "Niji no Oto" (虹の音, Sound of the Rainbow), which was released on January 1, 2014, was used as the opening theme to the special Sword Art Online: Extra Edition.

[23] Her seventh single "Ignite", released on August 20, 2014, was used as the first opening theme to the 2014 anime series Sword Art Online II.

[26] Her tenth single "Lapis Lazuli", released on April 22, 2015, was used as the ending theme to the 2015 anime series The Heroic Legend of Arslan.

[33] Her thirteenth single "Tsubasa" (翼, Wings) was released on July 20, 2016, and was used as the opening theme for The Heroic Legend of Arslan: Dust Storm Dance.

Her remaining appearances for 2016 and a scheduled performance at Anime Festival Indonesia 2016,[38] Animax Musix 2017 in Osaka in January 2017 were cancelled.

[39][40] On October 14, 2016, her management announced that she would put her musical career on indefinite hiatus following a final two concerts at Nippon Budokan on November 4 and 5, 2016.

[46] Her fifteenth single "Iris" (アイリス) was released on October 24, 2018; the song is used as the first ending theme to the anime series Sword Art Online: Alicization.

[56] Aoi's musical style has been influenced by her love of anime, as well as artists such as Evanescence, Slipknot, and Tomiko Van of Do As Infinity.

"Memoria" was released at a time when she did not perform live as she still hid part of her face, and taking this into account, she wanted to make a song where emotions could be expressed through her singing as opposed to her mouth.

For "Innocence", she wanted to produce a song that could express the growth and experiences that Sword Art Online's main characters Kirito and Asuna were encountering.