The Casey's Top 40 host was diagnosed with Parkinson's disease in 2007 and recently suffered from dementia and sepsis, which led to a battle between his daughter, Kerri Kasem, and wife, Jean Kasem, over his care.
A judge granted conservatorship to Kerri Kasem, who made the decision last week to pull Casey Kasem's life support.
Kerri Kasem announced her father's death on Twitter.
Early this Father's Day morning, our dad Casey Kasem passed away surrounded by family and friends. Even (cont) http://t.co/G4mxcmGWch— Kerri Kasem (@KerriKasem) June 15, 2014
"Early this Father's Day morning, our dad Casey Kasem passed away surrounded by family and friends. Even though we know he is in a better place and no longer suffering, we are heartbroken. Thank you for all your love, support and prayers. The world will miss Casey Kasem, an incredible talent and humanitarian; we will miss our Dad.
"With love, Kerri, Mike and Julie," she wrote.
For four decades, radio-listeners welcomed Casey Kasem into their homes every Sunday to count down the week's American Top 40 songs.
Fellow radio host and friend Art Laboe said Casey Kasem was always happy and had "a sparkle in his eye."
"It leaves a big blank space. The world will miss Casey Kasem and his great voice," Laboe told KTLA.