Mark William Calaway graduated from Waltrip High School in 1983, where he was a member of the basketball team.Calaway first married Jodi Lynn in 1989, and they had a son, Gunner, born in 1993, before the marriage ended in 1999. Calaway met his second wife, Sara, at a WWF autograph signing in San Diego, California.He eventually married her in a ceremony in St. Petersburg, Florida on July 21, 2000. Mark and Sara have two daughters together: Chasey, (born on November 21, 2002) and Gracie, (born on May 15, 2005).
As a wedding gift to mark, Calaway had his wife's name tattooed onto the front of his neck and has said this is the most painful tattoo he has ever had. Undertaker has several other tattoos: a gravedigger, which he refers to as "Original Deadman", skulls, a castle, and a wizard. When talking about his body art, he has said that there is kind of a medieval thing going-on on his arms. He also has a dancing skeleton on the back of his neck and has a tattoo on his stomach that says BSK Pride.
Aside from wrestling, Calaway has many hobbies and interests. He collects Harley-Davidson and West Coast Choppers motorcycles and purchased his first brand new motorcycle after defeating Hulk Hogan for the WWF Championship at the 1991 Survivor Series. Calaway has also had a custom motorcycle built for him by Jesse James, the founder of West Coast Choppers. He is a massive fan of Nick Cave and all his musical endeavors (The Birthday Party and The Bad Seeds). He also enjoys listening to bands like ZZ Top, AC/DC, Kiss, Black Sabbath, Guns N' Roses, Metallica, Judas Priest, Iron Maiden and Black Label Society. Other favorite music genres include, country and blues. As an avid boxing fan, Calaway was also the person who carried the Flag of the United States while leading Team Pacquiaoto the ring during the Pacquiao vs. Velázquez fight in 2005.This was also confirmed by fellow wrestler Batista in a televised interview for the Philippine news program TV Patrol World. Calaway is also an avid mixed martial arts fan and has attended several Ultimate Fighting Championship shows.
As The Undertaker had been absent from the WWE due to his 2007 arm injury, Calaway began getting into real estate with his partner Scott Everhart. Calaway and Everhart finished construction on a $2.7m building in Loveland, Colorado. The building, filled with upscale office space, is named the "The Calahart", a portmanteau of their last names. Calaway has said that being a television star certainly helps him in the real estate business, and he was quoted saying "by no means does it seal the deal, but people do want to sit down and talk with you. It helps us get to meet a lot of people and know what we’re trying to get accomplished.Calaway and his wife, Sara established The Zeus Compton Calaway Save the Animals fund at the Texas A&M College of Veterinary Medicine & Biomedical Sciences to help pay for lifesaving treatments for large-breed dogs.