Katsis, a Chicago native, managed and developed a wide variety of bands and musicians.
He helped guide groups like Jane's Addiction, the Backstreet Boys and The Smashing Pumpkins.
Katsis was born and raised in Chicago.
Billy Corgan posted a photo on Instagram, calling Katsis "Chicago royalty through and through."
Reports say Katsis died from complications from congestive heart failure at the age of 69.