Ahn was born in Seattle, Washington, and holds American citizenship,[4][5] although he later moved to South Korea with his family and spent most of his schooling years there.

Between 1997 and 1998, Son, Yoon Kye-sang and Kim Sun-a were recruited through auditions while Park Jin-young joined the group as their producer and mentor.

[17][18][19] He was invited back to be a guest DJ for the "Homecoming Day" special in 2015, in honor of KBS Cool FM's 50th anniversary.

Ahn, Son Ho-young and Park Joon-hyung were featured in the song "Memories and Remembrance", from Kim Tae-woo's mini album T-Virus.

[citation needed] He also joined Kim and Son to perform their song "Lies" on the Music Bank special celebrating 600 episodes[21][unreliable source?]

In May 2012, Ahn starred opposite Dave K. Wong as Gye Dong-hee, a friend to Ryu's Seung-hyuk in Channel A's Goodbye Dear Wife.

The group was first conceived after former H.O.T member Moon Hee-joon invited Ahn, Tony An (H.O.T), Eun Ji-won (Sechs Kies) and Chun Myung-hoon (NRG) to create a reality show version of the television series Reply 1997 in which they would meet up at a rented house to chat and reflect on their heyday.

[citation needed] Ahn's contract with his previous agency SidusHQ expired, and he signed with Box Media in March 2014.

[29] His appearances on television are largely on variety shows such as Infinite Challenge, Fantastic Duo,[30] King of Mask Singer and The Friends in Chiang Mai.

He reunited with HOTSechgodRG members Chun Myung-hoon and Tony An on Eun Ji-won's new travel reality show Plan Man.

[31] The group, except Eun, most recently met up at Moon Hee-joon's bachelor party, part of which was shown on My Little Old Boy, the reality show Tony An was participating in.