Gene Okerlund, who was inducted into the World Wrestling Entertainment Hall of Fame with Gagne in 2006, says his longtime friend died Monday in Minnesota.
WWE says Gagne turned professional in 1950 and won several regional championships before heading to the newly formed American Wrestling Association in 1960.
In the 1960s and 1970s, Gagne became a promoter and eventually became the sole owner of the AWA. He remained an active competitor until the early 1980s, holding the AWA World Heavyweight Championship 10 times between 1960 and 1981.
Okerlund calls Gagne one of the pioneers of professional wrestling who helped "put it on the map."