He was 68.
"My dear friend and TV brother Don Grady passed away today," posted his "My Three Sons" co-star Barry Livingston. "He was an inspiration to me in so many ways." Livingston played Ernie on the show.
Born Don Louis Agrati in in 1944, Grady was best known for his role as the middle son on the long-running series, which co-starred Fred MacMurray and William Demarest. Grady wrote some of the episodes and performed some of his own songs.
He appeared in a number of TV series, including "The Ann Southern Show," "Zane Grey Theater," "The Rifleman," "The Lucy Show" and "Simon and Simon."
Grady, who was signed to a composing, writing and singing contract by Capitol Records when he was 19, went on to a career as a composer following his TV career. He did the music for the Blake Edwards comedy "Switch," the theme song for "The Phil Donahue Show" and music for the Las Vegas stage show "EFX."
He released two albums, "Boomer: JazRokPop" in 2008 and "Homegrown," via Elektra Records in 1973,
