Don Grady, best remembered as Robbie Douglas from My Three Sons and as one of The Mickey Mouse Club‘s original Mouseketeers, died today after battling cancer, according to his family. He was 68. The San Diego native was 13 years old when he became a Mouseketeer in The Mickey Mouse Club. He went on to appear in several TV Westerns including Wagon Train, The Rifleman, Have Gun Will Travel and Dick Powell’s Zane Grey Theater. His biggest success came in 1960 when he was cast as middle son Robbie Douglas on the long-running TV show My Three Sons, starring Fred MacMurray, William Frawley and William Demarest. When the series ended in 1972, Grady pursued a career in his lifelong love, music, recording an album of his own material on the Elektra label titled Homegrown. Grady also starred in a national tour in Pippin, and had roles in the stage productions of Godspell and Damn Yankees.