Mustaine was born into a family of Jehovah's Witnesses on September 13, 1961 in La Mesa, California.He's now a born-again Christian.He has experienced alcohol and drug problems throughout his life, and briefly battled throat cancer in 2019. Mustaine has been married to Pamela Anne Casselberry since 1991, with whom he had two children, Electra and Justis.
Prior to forming Megadeth, Mustaine was the lead guitarist of Metallica but he did not appear on any of the albums. He was, however, credited as a writer on four songs from Kill 'Em All and two songs from Ride the Lightning.Wanting revenge on his old bandmates, he formed a heavier and faster band than Metallica.Sometime after his departure, he was able to take back one of his songs from Metallica,"The Mechanix",which is still performed every show to this very day.
Being kicked out of Metallica paved the way for his partnership with Dave Ellefson and Greg Handevidt. Ellefson was playing the opening bass line to Van Halen's "Runnin' with the Devil" in the apartment below Mustaine's.After stomping on the floor and shouting for them to stop, Mustaine, being hung over at the time, took a potted plant and threw it out of his window and hit the air conditioner of the apartment below shouting,"Shut up!"This resulted in the two coming up to Mustaine's apartment to ask where they can buy cigarettes. Mustaine replied "Yeah there's a store on the corner" and slammed the door in their faces.A few minutes later, they knocked on the door again, this time asking if they could buy him beer.Mustaine's reply: 'OK, now you are talking'. They spent the night talking about music, and soon after,the rest was history. Mustaine, Ellefson and Handevidt were bandmates in the first lineup of Megadeth.
Mustaine's second album, Megadeth's first hit
Mustaine rejoining Metallica for their 30th Anniversary
Megadeth's fourth album Rust in Peace was a massive success