Gentles began his career in the music industry as a musician; he was the vocalist and guitarist in the band Timmsie's First Time which broke up in 1995 and then The Selzers, which broke up in 2000. Matthew Romano, The Strokes' drum technician and back-up drummer, was also in both bands, playing drums. While in school, Gentles interned for future Strokes publicist Jim Merlis at
Geffen Records and New York music venue
Mercury Lounge. After graduating in 1999, he was hired by Mercury Lounge and shortly became their booker. He soon came in contact with The Strokes who asked him "three or four times to manage them" despite the fact that professional managers were courting the band. He became their manager in 2000 and, at the insistence of frontman
Julian Casablancas, had an equal share in the profits of the band, untypical of the music industry. Gentles was contracted to be The Strokes exclusive manager for five years and continued to manage them. He played a starring role in their 2003 music video "
The End Has No End." He has been considered to be "the sixth Stroke." After twenty years of managing The Strokes, Gentles and the band parted ways in October 2020. Gentles established his management firm, Wiz Kid Management, in 2003. In the early 2000s, he managed musicians
Adam Green and
Ryan Adams for a brief period. == Management roster ==