The band confirmed Sherman's passing in a statement shared on social media early Saturday.
“We of the RHCP family would like to wish Jack Sherman smooth sailing into the worlds beyond, for he has passed,” the group said on Instagram. “Jack played on our debut album as well as our first tour of the USA. He was a unique dude and we thank him for all times good, bad and in between. Peace on the boogie platform.”
A cause of death has yet to be revealed.
Sherman replaced Hillel Slovak as guitarist in 1983 ahead of the group's debut. He helped co-write the band's second album "Freaky Styley," which was released in 1985. Slovak, however, returned before the second album came out and Sherman exited the group.
The guitarist would later work on other Red Hot Chili Peppers albums, such as "The Abbey Road EP" and "Mother's Milk," but was not included when the group was inducted into the Rock & Roll Hall of Fame in 2012.
At the time, Sherman told Billboard it was "painful" to be left out. According to the outlet, only three of the eight guitarists who had worked with the band over the years were inducted.
"I'm not claiming that I've brought anything other to the band… but to have soldiered on under arduous conditions to try to make the thing work, and I think that's what you do in a job, looking back. And that's been dishonored. I'm being dishonored, and it sucks," he told the outlet.
Frontman Anthony Kiedis opened up about the situation in his memoir, writing that he believes the band's fate may have been different had Sherman not stepped in.
"God bless Jack, he did keep the band afloat for a year, and if he hadn't, the years to follow probably wouldn't have," Keidis wrote via Billboard.