"My Three Sons" is a TV Series that aired from 1960-1972.

On the long-running television sitcom "My Three Sons", Don was the big brother of Chip and Ernie and he died on Wednesday at his home in Thousand Oaks, Calif.He died at the age of68.

Mr. Grady, a versatile musician and singer who got his start in television as a Mouseketeers on "The Mickey Mouse Club," considered music his vocation and his acting career something of an accident.At 14, he was an aspiring musician in high school who played ukulele, drums, accordion and clarinet while acting on the side and auditioning for the part of Robbie Douglas, one of three sons of the wistful, pipe-smoking widower Steve Douglas.

Another actor was cast by the producers.Mr. Grady wrote that they needed to replace him for reasons he didn't know.I was summoned to an appointment at noon and was there by 3 p.m.I was cast as the new person.My acting abilities probably helped, but I still believe the reason I got the part was because of the cleft in my chin.

His place in the fictional family hierarchy shifted slightly over the course of the show, but he was still the main character.In the first few years, he was Mr. Douglas's middle son, until the role of the original older brother, Mike, was written out.Stanley Livingston, Barry's older brother in real life, took his place in the middle.

Mr. Grady's son was always cool.He was the teen idol of the cast, his face has been featured on the cover of teen magazines since his days as a Mouseketeers.Like Ricky Nelson,Robbie sang in a band and performed on the show.

The most frequent recipient of the fatherly advice that capped almost every episode was Mr. Grady, the family's earnest grown-up-in-training.

In the 13th episode of Season Four, Mr. MacMurray asked Rob if he really thought that was the right thing to do.It's not when you put it that way.

On June 8, 1944, Don Louis Agrati was born.His mother became a theatrical agent after his parents divorced.One of his sisters died in 2001.He is survived by his wife, children, mother, and sister.