According to a post on the Rainbow's Facebook page, Maglieri died Thursday morning "while surrounded by loved ones."
Maglieri, along with Elmer Valentine and Lou Adler, bought a restaurant known as the Villa Nova in 1972 and renamed it the Rainbow.
Rest in peace Mario Maglieri, 1924-2017, King of the Sunset Strip pic.twitter.com/TaZeEfg24f— Whisky A Go-Go (@TheWhiskyAGoGo) May 4, 2017
Maglieri was already known on the strip as manager of the nearby Whisky a Go Go, which was owned by Valentine.
The list of acts who played in these famed rock venues include: The Doors, The Byrds, The Temptations, Janis Joplin, Bruce Springsteen, Guns N' Roses, Motely Crue - and that's just to name a few.
A public memorial is scheduled to be held at the Rainbow on Sunday.
City News Service contributed to this report.