Mitchell was the last founding member still playing with the Portland, Oregon, band best known for its confounding rock cover of the R&B song “Louie Louie.”
“We are deeply saddened by Mike’s passing. He was the kindest and most generous man on the planet,” drummer Dick Peterson said in a statement.
“Mike is irreplaceable, and he will be greatly missed not only by us but the fans as well. Mike was a favorite for his comedic nature as well as his musicianship,” Peterson added.
“Louie Louie” has since been covered by everyone from the Beach Boys to the Grateful Dead to R.E.M.
Mitchell performed the famous jangly guitar solo in the middle of the song and continued to perform with different lineups of the band for more than 60 years.