Don Grady, who played Robbie Douglas on “My Three Sons” after serving as one of “The Mickey Mouse Club’s” original Mouseketeers and went on to a career as a musical performer and composer for television, died Wednesday in Los Angeles after a long battle with cancer. He was 68.

Grady had mastered several instruments by the age of 10, and Disney signed him for “The Mickey Mouse Club” when he was 13.

After ending his stint as a Mouseketeer, Grady guested on several TV shows, mostly Westerns, including “Wagon Train,” “The Rifleman,” “Have Gun, Will Travel,” “The Restless Gun” and “Dick Powell’s Zane Grey Theater.”

In 1960, he began a 12-year run as Robbie Douglas in “My Three Sons,” starring Fred MacMurray. Initially airing on ABC, the show switched to CBS in 1965.

In the show’s earlier years, Grady was actually the middle brother, with Tim Considine playing the oldest, Mike, and Stanley Livingston playing the youngest, Chip. When Considine departed, Barry Livingston became the adopted “third” son, and Grady became the cool, handsome and assured eldest brother that much of America adored.

During production of “My Three Sons,” Grady both appeared with his own band, the Greefs, on the series and wrote two original songs for the show. After the series ended, Grady and songwriter Gary Zekley formed the band Yellow Balloon, played with a folk-rock band called the Palace Guard and toured with a group known as the Windupwatch Band, which included Darryl Dragon.

After “My Three Sons” ended in 1972, Grady pursued a career in music and onstage. His showbiz composing credits include music for the Blake Edwards feature comedy “Switch” and the theme song for “The Phil Donahue Show.” Grady was also behind “EFX,” a multimedia stage show at the MGM Grand in Las Vegas that starred Michael Crawford, David Cassidy, Tommy Tune and Rick Springfield.

As a stage performer, Grady starred in a national tour in “Pippin” and had roles in productions of “Godspell” and “Damn Yankees.”

In 1973 Grady recorded “Homegrown,” an album of his own songs for the Elektra label. Grady’s “Boomer,” a collection of songs written for and about the baby boomer generation, was released in 2008.

“The one real through-line in his life was music,” Barry Livingston told the AP. “I would think Don would love to be remembered for his great music as much as a teen idol and television icon.”

Grady was born in San Diego as Don Louis Agrati and grew up in Lafayette, Calif. A sister, actress Lani O’Grady, died in 2001.

Grady was married twice. He is survived by his second wife, Ginny; a son and a daughter; his sister Marilou Reichel; and his mother, Mary Grady, a former talent agent.

(Associated Press contributed to this report.)