He also worked with French band Gojira and thrash icons Slayer during his career at Rick Sales Entertainment Group.
Longtime music manager Nick John died on Saturday, following a battle with pancreatic cancer.
"Thank you for your guidance, your wisdom, your never ending hard work and dedication to Mastodon, always pushing and reaching turning over every stone to make sure we were always protected and always had every opportunity any of us could dream of," wrote Mastodon on Facebook. "Thank you for making yourself available morning noon and night to handle every crisis or situation that ever came up. Thank you for being so passionate and believing in us with such enthusiasm that we considered you part of the band. Thank you for your calm demeanor, your level head and your sharp sense of humor. Thank you for showing all of us how to work our phones and computers with incredible patience via NJ solutions. Thank you for your smile and your infectious laugh but most of all, thank you for your unconditional love and friendship, we love you very much and are going to miss you more than we know. We love you Nick John. RIP."