In his youth, Shadows was notorious for his disorderly conduct and misbehavior. He was quoted as saying "I was in between a good kid and a terrible kid - I had a good heart, but a terrible attitude." He attended Huntington Beach High School after being expelled from his middle school in the eighth grade. As the band was just starting out, he was the darker character of the group (hence the name "Shadows") but he also wanted to incorporate his name, Matt, into his stage name. Matt was reduced to "M" because it had a better ring when combined with his stage name and ever since he has been known as M. Shadows.

Matt used to play the piano before he began to sing in his first band, "Successful Failure". When he was growing up, he listened to a lot of punk rock such as H2O and The Misfits and got into the metal scene when his father bought him Appetite for Destruction by Guns N' Roses after he had seen them on MTV's Headbanger's Ball.

In following years, Shadows formed a number of bands with Avenged Sevenfold's rhythm guitarist Zacky Vengeance. Zacky was previously a member of a punk group called 'MPA. While Shadows was in the previously mentioned "Successful Failure", The Rev was slotted to play drums (but was admittedly too good).^[2] While in this band he penned the song "Streets," which would later be recorded after Avenged Sevenfold was formed, and released on the first album, Sounding the Seventh Trumpet. The album was a mix of metalcore and punk rock but also includes a softer, more ballad-like song (Warmness On The Soul).