Heavyweight boxing championship records and statistics only universally recognized form of a world championship until July 2, 1921, when Jack Dempsey became the inaugural NBA Heavyweight Champion. The growing popularity of boxing led to a birth of various regional sanctioning organizations, with each recognizing their own champion. The major governing bodies were the National Boxing Association, formed in 1921, the New York State Athletic Commission, found after the Walker Law legalized prizefighting in New York in 1920, and the International Boxing Union, created in 1911 in Paris in attepmt create a unified international governing body for professional boxing. Both NBA and NYSAC made then-lineal champion Jack
Heavyweight boxing championship records and statistics of 23, 2019. These lists do not include "The Ring" and lineal championship fights after 1921, although they only include title streaks during which the champion captured "The Ring" or lineal title. Keys: As of 23, 2019. As of 23, 2019. Keys: "As of 24 September 2018". This list includes only major titles, and it does not include lineal championships after 1921. Below is a list of longest reigning heavyweight champions in boxing measured by the individual's longest reign. The list includes both "The Ring" and lineal championships. Career total time as champion (for multiple time champions) does not apply.