Before he died, Kasem — who suffered from Lewy body disease, a form of dementia with symptoms similar to Parkinson's — could no longer speak and suffered from an infected bedsore, while his wife publicly battled his children over his care.
Here's a look back at Kasem's long and successful career.
Kasem was the voice of Shaggy on TV's animated show Scooby-Doo for a total of 33 years.
He also did voice work for the cartoon series Transformers, but resigned because of what he perceived as negative stereotypes and offensive caricatures of natives of Arab countries.
On reading a script for an episode featuring an evil character named Abdul, Kasem wrote, "I asked the director, 'Are there any good Arabs in this script for balance?' We looked. There was one other — but he was no different than Abdul. So, I told the show’s director that, in good conscience, I couldn't be a part of that show."
American Top 40
American Top 40
During his time doing American Top 40, Kasem read more than 3,000 long-distance dedications.
"Keep your feet on the ground and keep reaching for the stars," was Kasem's signature sign off.
During his last broadcast of American Top 20, a show he hosted later in his career, he said, "Success doesn't happen in a vacuum. You're only as good as the people you work with and the people you work for. I've been lucky. I've worked for and with the very best."
American Top 40 began in 1970 and the first episode took more than 18 hours to record. Here are some samples of Kasem in the 1970s, '80s and '90s, and clips from his last show in 2009.