 The character of the original oldest brother, Mike (played by Tim Considine, who had earlier appeared with Grady in "The New Adventures of Spin and Marty") was gradually eased out of the series, and a new youngest son, Ernie (Barry Livingston), was adopted into the family.After leaving "My Three Sons" in 1971, 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 starring Michael Crawford, David Cassidy, Tommy Tune, and Rick Springfield.