Born in Nuneaton, Warwickshire, England[1] of Irish and Thai descent,[2] Keely grew up in the neighbouring town of Bedworth[3] before he and his mother moved to the U.S. state of Hawaii when he was five years old.

[2] Before signing a contract to Interscope Records with ...And You Will Know Us by the Trail of Dead, Keely primarily worked clerical office jobs in Austin while playing with the band at night.

[11] Although Keely does not speak Cambodian, he says the country is "a noisy place full of weird sounds – temples, monks chanting, loud speakers blaring, egg sellers and vendors.

...And You Will Know Us by the Trail of Dead quickly became known for their "anarchic" live shows and their sound, described by AllMusic's Jason Ankeny as "an unlikely but powerful combination of punk fury and prog rock ambition.

[19] On the sound of his first work without the band, while speaking with Steve Bell of Australia's The Music, Keely said that he was "given more freedom to explore other textures and stuff that I might not usually" while having "the liberty to create something that's outside of [Trail of Dead's] rock paradigm.

[21] Keely states in interviews that his biggest influences growing up were classic, progressive, and alternative rock; listening to bands like Pink Floyd, Rush, and The Replacements.

[25] Many tracks on the album Worlds Apart are about social unrest in the United States after the attacks of September 11th and consumer culture,[26][27] and Caryn Ganz of Spin described the writing on So Divided as "lyrically bleak.

He and the mother split up prior to recording IX, and Keely admits that the sense of melancholy and loss came into the album,[20] with songs like "The Ghost Within" and "The Dragonfly Queen" reflecting these feelings and events.

"[30] Keely is a fan of the X-Men and even noted that, as a reference to Secret Wars, he wanted to include a New Mutants character in the collage cover art of Worlds Apart.

[10] He believes the cover art and album packaging for Madonna played a part in ...And You Will Know Us by the Trail of Dead being noticed by Jimmy Iovine, co-founder of Interscope Records, which lead to their major label deal.