MacArthur’s agent, Richard Lewis, said the actor died in Florida of “natural causes,” but no direct cause was specified.
MacArthur, born Dec. 8, 1937, seemed destined to become an actor. He was the adopted son of playwright Charles MacArthur and Helen Hayes, an award-winning actress often referred to as “First Lady of the American Theatre.” Silent film star Lillian Gish was his godmother.
In a career that spanned more than four decades, MacArthur was most recognized for his role as Detective Danny “Danno” Williams on “Hawaii Five-0,” which aired from 1968 to 1980. Episodes often ended with detective Steve McGarret, the lead character, uttering what became a pop culture catch phrase: “Book ’em, Danno.”
Asked by the Hawaii Star Bulletin in 2003 about his fondest memories about working on “Hawaii Five-O,” MacArthur replied: “Living in Hawaii.”