Renowned for his announcing, ringside commentary and chats with such stars as Hulk Hogan and Jesse Ventura, his death at 76 was announced by the WWE company.
In a tweet, the company described him as "the most recognisable interviewer in sports-entertainment history."
"Mean Gene I love you my brother," wrote Hogan in his own Twitter tribute.
Others to pay homage included wrestler turned actor Steve Austin, who said he was "untouchable" and "simply the best".
Born Eugene Okerlund in 1942, "Mean Gene" came to prominence by interviewing the stars of the American Wrestling Association (AWA).
His nickname was coined by Jesse "The Body" Ventura, despite Okerlund being renowned for his friendly disposition.
Okerlund's long career spanned the AWA, WWE (World Wrestling Entertainment) and World Championship Wrestling (WCW).
He was inducted into the WWE Hall of Fame in 2006.
Okerlund, who had kidney transplants in 1995 and 2004, made his last appearance on WWE TV in January 2018.
Yet he continued to make personal appearances and was seen in a soft drinks commercial alongside comedian Kevin Hart last May.