Grady was born Don Louis Agrati in San Diego, California. He grew up in Lafayette, California, before being signed by Disney and leaving the area. Besides The Mickey Mouse Club, his early acting credits included several Western series, including John Payne's The Restless Gun, Dick Powell's Zane Grey Theater, Wagon Train and The Rifleman. He also had a role in the NBC medical drama, The Eleventh Hour.
Originally cast as the frustrated middle brother on My Three Sons, he became the "confident elder brother" with the departure of Mike (Tim Considine, who had earlier appeared with Grady in The New Adventures of Spin and Marty), and the adoption of Ernie (Barry Livingston), who became the new "third son."
He not only wrote and performed many of his original songs on My Three Sons, he stepped behind the cameras to write some episodes as well.
During production of My Three Sons, Grady both appeared with his own band The Greefs on the series, and was the drummer for The Yellow Balloon, whose self-titled song became a minor hit during 1967.
After My Three Sons ended in 1972, Grady pursued a musical career. His works included music for the Blake Edwards comedy film Switch, the theme song for The Phil Donahue Show and for EFX, a Las Vegas multimedia stage show which starred Michael Crawford, David Cassidy, Tommy Tune, and Rick Springfield.
He wrote and produced Homegrown, an original album released as Don Agrati on Elektra Records. The success of this album abroad led many European bands to cover Don's songs, one of which garnered a gold record for the Dutch band, Lucifer.
Soon, he began composing music for the live stunt shows at Universal Studios Hollywood and Florida. His score for The Wild, Wild, Wild West show ran for 14 years. Don was also the Music Director for George Lucas Live, a 3-hour arena event for which he conducted the London Symphony Orchestra.
Don's first major television score, co-written with Don Nemitz, was The Revolutionary War, a 6-hour film which won the Cable Ace Award for Best Documentary. He followed that up scoring the Emmy Award-winning documentary, Why Dogs Smile & Chimpanzees Cry.
Don returned to the Disney family in 2001, composing music for more than 30 Disney DVD's including the last five Special Platinum Edition releases, The Emperor's New Groove, Beauty and the Beast, The Lion King, Aladdin, and Jungle Book.
In the fall of 2008, Grady released Boomer: JazRokPop, a collection of songs written for and about the baby boomer generation. Boomer was his first original album as an artist since Homegrown in 1973.
After a long battle with cancer, Grady died on June 27, 2012, , just 19 days after his 68th birthday.
For more on Don (Robbie!) visit his Website at -