3. LL Cool J
Years on Def Jam: 1985-2008
Signature Def Jam Song: "Mama Said Knock You Out" (1990)
Hip-hop to Hollywood but is he good? Def Jam is the house that L built. Along with T La Rock, LL was the first artist on the Def Jam label with "I Need A Beat." His subsequent recordings are a reminder of how hip-hop changed the pop music landscape forever.