Glen Danzig aka Allen Anzalone is another worldwide known American-Italian rock singer. Previously Danzig was a leading vocal for the infamous band "The Misfits"...
Speaking about The Misfits, their famous guitar player is also another Italian-American who goes by the name Paul Caiafa aka Doyle Wolfgang von Frankenstein...
Both Misfits and Danzig solo are classic!
Here's my favorite Misfits track;
Another classic group from the heavier rock realm that's almost all Italian American (with the exception of rhythm guitar player Scott Ian, who's Jewish) is Anthrax;