Don Grady, who was one of television's most beloved big brothers as Robbie Douglas on the 1960s hit My Three Sons died Wednesday in Thousand Oaks, California at the age of 68.
Grady was born Don Louis Agrati in San Diego before his career as a Mouseketeer on the "Mickey Mouse Club" at age 13. He later filled the role of Robbie Douglas on My Three Sons from 1960 to 1971.
The sitcom starred the late Fred MacMurray as a widowed aeronautical engineer struggling to raise three older boys.
My Three Sons is one of the longest-running family sitcoms in the history of television. It debuted on ABC, moved to CBS in 1965 when ABC refused to finance the series' switch to color. This successful show went on to make 12 seasons and 380 episodes altogether.
It is second only to The Adventures of Ozzie and Harriet as TV's longest-running (live-action) family sitcom.
Grady made a various guest appearances on TV series in the 1970s and 1980s, but worked mainly as a musician and composer.
During those years, he wrote the theme song for "The Phil Donahue Show", music for the Blake Edwards film "Switch" and the popular Las Vegas show "EFX," a showcase for "Phantom of the Opera" star Michael Crawford.
Grady leaves behind wife Ginny, children Joey and Tessa, his sister Marilou Reichel, her husband Meryl, their daughter Kelly and husband Mike Edwards and his mother Mary.
Watch a clip of Don Grady in My Three Sons below: