AGAAGA

In 2012 鄭融 sent "第五類", composed by AGA, to the radio stations. This was the first song AGA composed that was sent to the stations. The same year Hacken Lee, 薛凱琪 and 連詩雅 also took up AGA's writing, one after another. After 黃劍濤, a senior executive at Universal Music, heard "我願意", which AGA had composed for Kary Ng, 黃劍濤 arranged through 舒文 to meet AGA, and this in the end brought AGA to Universal Music. In 2013 AGA signed with Universal Music and formally debuted, shortening the English name Agatha to the stage name AGA, moving from a musician behind the scenes to a singer-songwriter in front of them, and chose five songs from demos AGA had written, included in the work of the same name, "AGA". That work was released digitally on September 2, 2013, and the physical edition was issued on January 7, 2014. Every song was composed by AGA and produced by 舒文. At the Ultimate Song Chart Awards Presentation for 2013 AGA won the Ultimate Song Chart New Force Gold Award, and while receiving the award sang on the spot "能說不的秘密", a fast song AGA had written.

In July 2014 "一", composed and sung by AGA, was sent to the radio stations, and after that reached the top of the pop charts of four electronic-media outlets in Hong Kong. It was AGA's first four-station chart-topper. AGA also brought in Gin Lee to sing the song with her as a duet in a new arrangement, retitled "一加一". After that a first three-inch single, "One", was released, containing "一" and "一加一", and Eason Chan was asked to narrate the theatre version of "一加一". "一" won the Metro Hits Airplay Index Award at the Metro Radio Hits Music Awards 2014, and placed third on the professional-recommendation Ultimate Top 10 at the Ultimate Song Chart Awards Presentation for 2014. In March 2016 AGA released the album "Ginadoll", containing four new songs. At "Ginadoll喜樂發佈會" AGA announced that a first ticketed solo concert, "AGA Ginadoll Concert Live", would be held at MacPherson Stadium on July 29 and 30, 2016. The same year the live album "Ginadoll Concert Live" was also released. "獨一無二", sung with Gin Lee, won a Metro Hits Song award at the Metro Radio Hits Music Awards 2016 and a Top Ten Chinese Gold Songs award at the 39th Top Ten Chinese Gold Songs Awards ceremony. At the 39th Top Ten Chinese Gold Songs Awards concert AGA also won the CASH Best Singer-Songwriter Award. In 2016 AGA appeared in the film "此情此刻", playing 大Dee.

"3AM" placed sixth on the professional-recommendation Ultimate Top 10 at the Ultimate Song Chart Awards Presentation for 2017, and won a Top Ten Chinese Gold Songs award at the 40th Top Ten Chinese Gold Songs Awards ceremony. At this edition AGA won the Outstanding Pop Singer Award for the first time. On January 22, 2018, AGA released the fully self-written album "Luna". The songs on it are all writing and demos AGA made in the small hours. "無期" placed seventh on the professional-recommendation Ultimate Top 10 at the Ultimate Song Chart Awards Presentation for 2018, and "小問題" won a Top Ten Chinese Gold Songs award at the 41st Top Ten Chinese Gold Songs Awards ceremony. AGA also won the Ultimate Song Chart Female Singer Bronze Award and the Ultimate Song Chart Singer-Songwriter Silver Award for the first time, and won the Outstanding Pop Singer Award again. "Tonight" won a Top Ten Chinese Gold Songs award at the 42nd Top Ten Chinese Gold Songs Awards ceremony. AGA also won Hits Female Singer for the first time, and again won the Ultimate Song Chart Female Singer Bronze Award, the Ultimate Song Chart Singer-Songwriter Silver Award and the Outstanding Pop Singer Award. In 2020 the album "So Called Love Songs" was released.

AGA had planned to hold a first Hong Kong Coliseum concert, "AGA Round Midnight Live 2020", in April 2020, and wrote the theme song "Mad" for it. It was later cancelled because of the COVID-19 pandemic. The same year AGA was nominated for "大中華地區最受歡迎藝人" at the 2020 MTV Europe Music Awards. At the Ultimate Song Chart Awards Presentation for 2020, held behind closed doors at KITEC, AGA won the Ultimate Song Chart Female Singer Gold Award and the Ultimate Song Chart Singer-Songwriter Gold Award, and with "See You Next Time" placed sixth on the professional-recommendation Ultimate Top 10. At the 43rd Top Ten Chinese Gold Songs Awards AGA also won the Top Ten Chinese Gold Songs Female Singer Bronze Award. In 2021 three record companies under HKRIA and TVB broke the ice, and AGA's new song "CityPop" was then sent to TVB. The same year AGA was a mentor on the TVB singing talent show "聲夢傳奇". The Hong Kong Coliseum concert "AGA Gaia Live 2022", planned for January 2022, was again cancelled because of the pandemic. "Tomorrow", the theme song written for that concert, became AGA's first five-station chart-topper. In May the same year AGA renewed with Universal Music.

In 2023 it was the tenth anniversary of AGA's debut as a solo artist, and the song "MIZU" was released. In August the same year AGA held a solo concert at the Hong Kong Coliseum for the first time, "AGA ONEDERFUL LIVE 2023". On January 19, 2024, AGA released a fifth studio album, "Agatha", and the same year also released the album "Onederful Live 2023". In 2025 the EP "Gas Station Diner" was released, and on August 22 the same year a sixth studio album, "Writer’s Block", was released.

After the Universal Music contract ran out, AGA did not renew for the time being, ending a 12-year working relationship. In 2026 AGA took part in the mainland China television programme "國樂無雙".