Mike was 10 years old when he began playing guitar. During his high school years, he played quads in the marching band and became co-captain of the drumline his junior and senior year. In 1999, he moved to Santa Barbara where he attended Santa Barbara City College for the following three years. Shortly after moving, Mike began playing in a progressive death metal band called Cystrot alongside guitarist/vocalist Sam Williams. Williams was currently enrolled in the music program at Santa Barbara City College and influenced Spreitzer to do the same. In 2001, while still in attendance at Santa Barbara City College, Michael decided to pursue a degree in music. In 2002, he transferred to UCSB to continue his studies.
Halfway through 2001, Mike decided to quit Cystrot due to the lack of motivation from the other members and joined another local heavy metal band from Santa Barbara called Grolby alongside future DevilDriver bandmates John Boecklin, Jon Miller, and Jeff Kendrick. Unfortunately, Grolby broke up eight months after Spreitzer joined. At this point, Mike went on to form an industrial-metal band called No Love Lost with friends Cliff Ross and Dan Bellinger. Although an album’s worth of material was written and recorded, nothing was ever released.
In April 2004, DevilDriver was about to embark on their first European tour opening for Swedish heavy metal band In Flames. Two days before the tour began, DevilDriver’s guitarist Evan Pitts was forced to withdraw from the tour due to personal reasons, leaving the band without a second guitar player. At the time, Jon Miller and Jeff Kendrick lived with Spreitzer when not touring with DevilDriver. When Mike heard that Pitts would not be going on the European tour he immediately offered to fill in temporarily for the duration of the tour. Shortly after DevilDriver returned to Santa Barbara, Pitts had decided not to continue with the band and Spreitzer became a permanent member.
Since joining DevilDriver in 2004, Mike has continued to tour with the band and contribute on the albums The Fury of Our Maker’s Hand, The Last Kind Words, Pray for Villains, and Beast. He has also written and recorded music for small movie projects including the documentary Tokyo Comedy Store (Director: Brian Christopher Anderson) that has been featured on the Documentary Channel in the United States. In 2009, Mike co-wrote three songs featured on the video game MX vs ATV Reflex soundtrack alongside Raymond Herrera, Christian Olde Wolbers, and Jeff Kendrick.
In 2012, Mike worked with London-based alternative rock band ESO and featured on their debut single, ‘We are watching you’, from their new album, ‘Nothing left to lose’.