Prior to joining WMG, Cohen was head of Island Def Jam, where he led the growth and cultivation of its world-class roster of artists and record labels, including Def Jam, Island Records, Roc-A-Fella, Lost Highway, The Inc, American, Def Soul, Def Soul Classics to Roadrunner records which produced the multi-platinum Nickelback. Known for developing and guiding the careers of many early pioneers of rap music, including LL Cool J, Public Enemy, Run DMC, Kurtis Blow and the Beastie Boys, Cohen is widely credited with expanding Island Def Jam beyond its hip-hop roots to include a wider range of musical genres. These top artists include Melissa Etheridge, Elvis Costello, Bon Jovi, Mariah Carey, Shania Twain, Ashanti, Everlast, Ryan Adams, Nickelback, Slipknot, Hoobastank, Sum 41 and Slayer. After becoming President of Def Jam records in 1988, a label founded by Russell Simmons and producer Rick Rubin, Cohen signed acts such as DJ Jazzy Jeff and the Fresh Prince, Eric B and Rakim, EPMD, Slick Rick and 3rd Bass to the label.