Horwich was born and raised in Seattle, Washington. He watched many Bruce Lee films growing up and entered Dojo Kai Korean traditional martial arts classes. Growing up, Horwich had little interest in school due to low opinions of his teachers. Unmotivated, lost and without a concrete path to embark on, he began to experiment with drugs and alcohol. Things were not looking bright as his poor choices continued to lead him in the wrong direction. He then garnered interest for Brazilian Jiu-Jitsu (BJJ) at the age of 17 and saved up enough money to learn from none other than Royce Gracie himself. After that, he reluctantly made an unwise decision and was placed in jail for thirty days for fighting and breaking windows. He served his time and chose to relocate to Seattle, Washington with the intention of starting a band. While there, he performed odd jobs and lived in squats as he crossed-paths between becoming either a musician or martial artist. He then eventually experienced a religious conversion as a self-described "spiritual" Christian and rededicated himself to a successful, focused career in martial arts.
Horwich developed his impressive skills as a submission specialist training with Team Quest as well as BJJ black belts B.J. Penn and Eddie Bravo. He has also trained extensively with accomplished Kickboxer and Muay Thai Fighter Chris Reilly. Matt Horwich earned the nickname "The Fighting Hippy" due to his extremely unusual personality and interests.
Before signing with the International Fight League's Portland Wolfpack, Matt Horwich amassed a strong record of 15-6-1 fighting in small promotions. His popularity and well-fought 5-3 record while there led the IFL to match him against Benji Radach at the World Grand Prix Finals to determine the first middleweight champion. Horwich outstandingly defeated the noted striker by Knockout in the second round, becoming the IFL's first ever middleweight champion.
Matt Horwich then signed with the UFC after the IFL folded and made his debut at UFC 90. His opponent, none other than the latest IFL middleweight champion Dan Miller. Horwich came close to sinking in a fight-ending choke in this exciting bout as the clock suspensefully ticked at the final part of the second round. Despite his wholehearted efforts, Miller controlled most of the first and third rounds and took the unanimous decision. Horwich then made his second UFC appearance at UFC Fight Night: Condit vs. Kampmann against Ricardo Almeida which resulted in a second decision loss and his release from the company.
After that, he debuted with Bellator and then Aggression MMA where he came back with a solid, split-decision victory over Jason Lambert. This very well-fought rematch took place in Alberta, Canada as Horwich successfully returned to his winning ways.
Horwich fought Tom 'Kong' Watson at BAMMA3 as a late replacement for Alex Reid on 15 May 2010 and lost. It was his first fight in Britain.
Horwich beat Thales Leites, former UFC Middleweight contender, in an upset on August 14.
On September 9, 2010, Horwich fought Bellator season two semifinalist Eric Schambari, losing via split decision.
Horwich then defeated Jake Rosholt by technical knockout in the third round at Xtreme Fight Night – Rosholt vs. Horwich in November 2010.
At Shark Fights 14: Horwich vs. Villefort on March 11, 2011, Horwich squared off with UFC and WEC veteran Danillo Villefort, losing by unanimous decision after being controlled both on the feet and the floor for the entirety of the 15-minute affair.
Horwich faced a rematch with Jake Rosholt at Shark Fights 17: Horwich vs. Rosholt 2 on July 15, 2011, losing by unanimous decision. Rosholt used his wrestling to neutralize any attempt at a takedown and utilized a much improved striking game to win the nod from the judges.
Horwich fought Piotr Strus at KSW 25 on December 7, 2013. Though the fan favorite coming into the fight, Horwich lost by majority decision.
Matt Horwich was married the day after his first attempted defense of the IFL Middleweight Championship. Horwich is often described as a hippie who frequently quotes Bible passages and personal aphorisms in conversation. His hobbies include playing guitar and writing music and poetry, mostly themed around his interest in quantum mechanics.