The father of the famous Brown family suffered a seizure on Sunday night (7 February).
His son Bear announced the news on his Instagram account, writing: "We are heartbroken to announce that our beloved patriarch Billy Brown passed away last night after suffering from a seizure.”
He added, alongside a photo of Billy with his wife, Ami: "He was our best friend – a wonderful and loving dad, granddad and husband and he will be dearly missed.
"He lived his life on his terms, off the grid and off the land and taught us to live like that as well. We plan to honour his legacy going forward, and to continue with his dream. We ask for privacy and prayers during this painful time. God Bless Everyone!"
Alaskan Bush People is a US reality series following Billy’s naturalist family as he lives life removed from civilisation alongside Ami and their seven children.
A spokesperson for Discovery Channel, who airs the show, said: "We are devastated to hear of Billy Brown's sudden passing. He has been part of the Discovery family for years – a trailblazer, a lovely man and most definitely one of a kind.
“Our heart is with his family and those that knew him and loved him as they deal with this devastating loss."
Brown had been on the series since it began in 2014.