McMahon's trademark introduction is known worldwide
Ed McMahon, Jonny Carson's sidekick for 30 years on NBC's The Tonight Show, has died at the age of 86.
Best known for his enthusiastic catchphrase "Here's Johnny!", McMahon was also familiar as the host of TV talent show Star Search.
His publicist, Howard Bragman, said McMahon died on Tuesday at the Ronald Reagan UCLA Medical Center surrounded by his family.
He said McMahon suffered "a multitude of health problems" in the past months.
In 2007, he fell and broke his neck and as a result of not being able to work, he defaulted on mortgage payments on his Hollywood mansion.
Earlier this year, he settled out of court with the Cedars-Sinai Medical Center in Los Angeles over a claim that staff failed to treat him properly. The star also claimed the hospital botched two operations which left him in pain.
In March, he was treated in intensive care in hospital after suffering from pneumonia.
At the time, Mr Bragman declined to comment on reports that the TV star was also suffering from bone cancer.
Johnny Carson died in 2005, after losing a battle with the respiratory disease emphysema.
McMahon was born in 1923 in Detroit, Michigan.
He worked as a bingo caller during the school summer holidays and went on to study electrical engineering in college.
In World War II, McMahon was a Marine Corps fighter pilot but spent much of his service working as an instructor and test pilot.
After graduating from university in Washington DC, he became a local TV producer in Philadelphia.
After being called up for service again during the Korean war, McMahon returned home and got his big break on ABC daytime show Who Do You Trust? McMahon was the announcer alongside rising star and host, Johnny Carson.
The pair teamed up again, four years later in 1962, this time on NBC's late night talk show, The Tonight Show. Their on-screen partnership lasted 30 years.
Besides his wife, Pam, McMahon is survived by children Claudia, Katherine, Linda, Jeffrey and Lex.
Mr Bragman said no funeral arrangements have been made yet.