He died from an undiagnosed aortic dissection which is a tear in the wall of the aorta. He underwent surgery and died on September 11, 2003, just six days shy of his 55th birthday. In the years that he worked, John Ritter was a brilliant comedian and a passionate actor, who wanted to make everybody laugh. Shortly before his death, his eldest son, Jason Ritter, was cast in the role of Kevin in the highly-rated drama Joan of Arcadia (2003).