Mark William Calaway (born March 24, 1965), better known by the ring name The Undertaker is an American retired professional wrestler. Widely regarded as one of the greatest professional wrestlers of all time, Calaway spent the vast majority of his career wrestling for WWF/E, and is best known for his critically acclaimed "Deadman" Undertaker gimmick, for which he was inducted into the WWE Hall of Fame in 2022. Calaway remains employed for WWE through a 15-year contract signed in 2019.Calaway began his career in 1987, working under various gimmicks for World Class Championship Wrestling (WCCW) and other affiliate promotions. He became USWA Unified World Heavyweight Champion and WCWA Texas Heavyweight Champion during this time. After signing with World Championship Wrestling (WCW) in 1989, he had a brief stint in the mid-card as "Mean" Mark Callous, before joining the World Wrestling Federation (WWF, now WWE) in 1990.

Calaway was rebranded as "The Undertaker" once joining the WWF. As one of WWE's most popular and enduring characters, The Undertaker was known for his undead, funereal, macabre persona, which gained significant mainstream popularity and won him the Wrestling Observer Newsletter award for Best Gimmick a record-setting 5 years in a row. The longest-tenured wrestler in company history at 30 years, The Undertaker is one of the most prominent figures of the Attitude Era–a high ratings, envelope-pushing generation of the WWF/E in the latter 1990s. Calaway expanded on The Undertaker gimmick by assuming a biker identity, dubbed "American Badass", in 2000. Calaway resurrected The Deadman Undertaker in 2004, with residual elements of American Badass Undertaker remaining.

For the better part of his career, The Undertaker was observed as a focal point of WWE's flagship annual event, WrestleMania, where he became esteemed for The Streak—a series of 21 straight victories. He is also known for pairing with his in-storyline half-brother Kane, with whom he had alternatively feuded and teamed off and on with as The Brothers of Destruction from 1997 through 2020. During his active career under The Undertaker gimmick, Calaway won the WWF/E Championship four times, the World Heavyweight Championship three times, the Hardcore Championship once and the World Tag Team Championship six times. He also won the Royal Rumble match in 2007. He is one of WWE's most prolific pay-per-view performers, headlining several pay-per-view events, including WrestleMania on five occasions.The Undertaker retired from professional wrestling in 2020 and made a farewell appearance at that year's Survivor Series, 30 years to the day from his on-screen debut for the company at the same pay-per-view brand. The Undertaker was inducted in the WWE Hall of Fame as the headline inductee for the class of 2022.