Who was the head "Jackass" on the show of the same name?

Johnny Knoxville was the head “Jackass” on the television show Jackass.

Knoxville was the project’s central performer and one of its principal creators. The series grew out of a collaboration among Knoxville, director Jeff Tremaine, and skateboarding magazine contributor and performer Bam Margera, among others. It premiered on MTV in 2000 and built its identity around dangerous stunts, practical jokes, endurance tests, and deliberately crude comedy.

Knoxville often functioned as the show’s unofficial leader and recognizable frontman. His stunts included testing protective equipment and confronting hazards that were intentionally designed to look reckless, although productions used planning and safety measures. His screen persona helped turn the ensemble into a broader media franchise, including multiple Jackass films and spin-off projects.

The wording “head Jackass” is informal rather than an official title, since Jackass was an ensemble show and Jeff Tremaine was its director and producer. Nevertheless, Knoxville is the standard answer in trivia because he was the best-known central performer and the figure most closely identified with the series.