Carl Patrick O'Brien, also known as Cubby O'Brien, was the youngest of three sons born to Haskell "Hack" O'Brien, a professional drummer. His oldest brother, Haskell Junior, played the trumpet, while his middle brother, Warren, played the drums. Cubby received his nickname from his mother, who thought he resembled a bear cub as an infant.
The family resided in Sun Valley, California. Cubby began playing drums at the age of five, attending the Carl Babcock Music School in Sherman Oaks, where his father taught. At eight years old, he performed with the Roger Babcock Dixieland Band on the Spade Cooley television show, and at rallies and benefits, including the 1954 Screen Actors Guild Christmas benefit.
One of these performances caught the attention of a Disney producer, who later told Walt Disney about Cubby. Walt Disney then saw Cubby perform on the Ray Bolger Show and requested an audition for the Mickey Mouse Club. Cubby was the only musician among the Mouseketeers allowed to play on-camera, possibly due to his exceptional skill.
As a Mouseketeer, Cubby appeared in the Disney film Westward Ho, the Wagons in 1956, alongside Tommy Cole, Karen, and Doreen Tracey. He also appeared in the Disneyland 4th Anniversary episode and was slated to play a role in the proposed film Rainbow Road to Oz.
After the Mickey Mouse Club, Cubby joined The Lawrence Welk Show, where he stayed for two years. He then had his own combo and toured with Spike Jones, a manic bandleader and composer. Cubby worked with various artists, including Ann Margaret, Jim Nabors, and The Carol Burnett Show.
He married three times, first to Marilyn Miller, with whom he had a daughter, then to Terry Wilemon, and finally to Holly in 2002. Cubby continues to work as a drummer, playing for touring Broadway shows and with Bernadette Peters. He has participated in many Mouseketeer Reunion shows, including the 50th Anniversary in 2005.
