Casey Kasem: Cheerful, gentle-mannered DJ whose long-running radio show made him king of the chart countdown

Kasem with his Radio Icon Award at the 2003 Radio Music Awards in Las Vegas (AP)

With his cheerful manner and gentle voice, Casey Kasem became the king of the US top 40 countdown with a syndicated radio show that ran for decades. Beginning in 1970, American Top 40, with Kasem's soft, homely voice counting down the hits, was a refuge from shock jocks and screaming big-city radio voices. It broadcast on around 1,000 stations at its peak. In his sign-off, Kasem would tell listeners: "And don't forget: keep your feet on the ground and keep reaching for the stars."

American Top 40 expanded to hundreds of stations, including Armed Forces Radio, and continued in varying forms into this century. He stepped down from the show in 2004 and retired altogether in 2009. His voice was also heard in cartoons such as Scooby-Doo (he played Shaggy) and in numerous advertisements.

The son of Lebanese Druze immigrants, Kasem spoke out for greater understanding of Arab-Americans. "Arab-Americans are coming out of the closet," he said in 1990. "They are more outspoken now than ever before. People are beginning to realise who they really are, that they are not the people who yell and scream on their nightly newscast."

He was born Kemal Amin Kasem in 1932 in Detroit. He began his broadcasting career in his high school radio club and was soon a disc jockey on WJBK in Detroit, initially calling himself Kemal Kasem. In a 1997 visit to high school students in Dearborn, Michigan, home to a large Arab-American community, he was asked why he changed his name to Casey. "It didn't sound like a DJ," he replied. "It wasn't hip. So we decided I'd be 'Casey at the Mic'."

In recent years, Kasem was trapped in a feud between his adult children and his second wife, the former actress Jean Thompson. In 2013 his children filed a suit to gain control of his health care, alleging that he was suffering from Parkinson's disease and that his wife was isolating him from friends and family. He also suffered from Lewy Body Disease, a form of dementia.

Last month a judge temporarily stripped his wife of her caretaker role after she moved him from a medical facility in Los Angeles to a friend's home in Washington state. Casey Kasem developed a severe bedsore there and was in critical condition by the time he was taken to hospital early this month. It was a sad, startling end for a man whose voice had entertained and informed music lovers around the world.

Kemal Amin "Casey" Kasem, broadcaster and actor: born Detroit 27 April 1932; twice married (four children); died Gig Harbor, Washington 15 June 2014.