Karges is married to Julie Holland-Karges. They have three sons: Matthew Jr., Andrew and John. In 2002 Karges and his wife created the charity 'Music For A Cure' which raises money to support music therapy programs in hospitals. They also find instruments for kids in hospitals who can't afford them. To help aid the organization, Karges has organized exclusive Sugar Ray concerts (where ticket sales go to MFAC), as well as several eBay auctions of his signed bass guitars.