Hanneman was born January 31, 1964 in Oakland, California and grew up in Long Beach, California in a family containing several war veterans: his father fought in Normandy during World War II and his brothers in Vietnam, making warfare a common conversation topic at the dinner table. War films were popular on TV at the time, and Hanneman often joined his brothers in constructing and coloring tank and plane models. His interest in warfare and military history is attributed to his upbringing. In a 2009 interview with Decibel Magazine, he states his father is German, but fought for the allied side in World War II. In the same interview, he also goes into detail of what district of Germany his father and grandparents hail from. His grandfather was fluent in German.
Hanneman approached Kerry King in 1981, when King was auditioning for a band. After the try-out session, the two guitarists started talking and playing Iron Maiden and Judas Priest songs. Slayer was born when Hanneman asked “Why don’t we start our own band?”, to which King replied “…Fuck yeah!”. In 1984, Hanneman, Dave Lombardo and Suicidal Tendencies’s guitarist Rocky George had a brief punk side project called “Pap Smear” – the band was due to start recording when Hanneman was advised to avoid the side project by Slayer’s producer, Rick Rubin, who is quoted as saying “Ahhhh, don’t do it, man — this is the kind of thing that breaks bands up!” Hanneman took Rubin’s advice, and later used two of the songs on Slayer’s 1996 album Undisputed Attitude.
In 1997 Hanneman married Kathryn , whom he had met in the early 1980s. The couple had no children and lived in Los Angeles, forty minutes away from King. Kathryn stayed at home when Slayer toured; Hanneman claimed to prefer this, having said that when he came home, she was “all brand new again”. Kathryn had toured with the band twice in twenty years.
Hanneman and Slayer vocalist/bassist Tom Araya are reformed cocaine and pill abusers. They decided to quit when they realised “this can lead to only death or something, this is going too far”. Hanneman was a long-time fan of the Oakland Raiders.
In early 2011, Hanneman contracted necrotizing fasciitis. According to the band, doctors say that it likely originated from a spider bite. In the light of this situation and Slayer’s upcoming participation in the Australian Soundwave Festival tour that was set to kick off on February 26, the band made the tough decision to play the dates without Hanneman, and on February 16, 2011 brought on Gary Holt (guitarist of the band Exodus) to fill in for him. Pat O’Brien joined as Slayer’s temporary second guitarist when Holt left the tour to play with Exodus.
Hanneman withdrew from active touring in early 2011 after he contracted necrotizing fasciitis, a debilitating skin disorder. By 2012, bandmate Tom Araya had announced his recovery from the disease, however later in February, 2013, Kerry King revealed continuing health problems that kept him from working with Slayer. Hanneman died on May 2, 2013 near his home in Southern California’s Inland Empire. He was in a local hospital and suffered. It is not known if the skin ailment was connected to his liver failure.