Mickey's father was the famous actor Mickey Rooney (Sr), his grandfather Joe Yule, a Scottish born Vaudeville player. Mickey Jr was reportedly born Joe Yule III, though his father had long ago legally changed his name to first, Mickey McGuire, then later, to Mickey Rooney. His mother, Miss Alabama of 1944, was Betty Jane Rase from Birmingham, who later sang professionally under the name B. J. Baker. The couple met when PFC Mickey Rooney was in Alabama for training during WWII.
Mickey Jr bore little resemblance to his father, unlike younger brother Tim Rooney. He wasn't button cute as a child like Tim, being instead taller and more somber. Mickey Jr showed an aptitude for music, apparently derived from their mother's side of the family. He first learned to play the ukulele from chords taught by his maternal grandmother, and later taught himself to play guitar and other instruments. After his parents divorced in 1949, Mickey's mom married Barney Kessel, a jazz guitarist, who would further Mickey's musical education.
How Mickey came to be selected for the show is unknown to me. Walt Disney was adamant about not automatically hiring the children of his acquaintances among Hollywood's elite. Candice Bergen, for one, was not selected, though she auditioned and her father Edgar Bergen lobbied for her. It seems likely that Mickey auditioned and was hired as one of the original Mouseketeers by May 1955.
It's hard to gauge Mickey's qualities as a young performer, as he appeared in so few skits. He was in the roll call for the Mouseketeers' debut at Disneyland, but didn't dance in the introductory segment (though he did in the rehearsal films). The only sequence with him readily available today is Circus Day from the First Week DVD, where he and fellow short-timer Paul Petersen take part in acrobatics. This sort of action rough-and-tumble seemed to suit both Paul and Mickey better than musical variety. If there had been more of it to keep them occupied, they might have lasted longer on the show. As it was, Paul was dismissed sometime after July 17, 1955, to be replaced by Tim Rooney.
Mickey Jr and brother Tim were themselves dismissed a few weeks later, after they went into the paint department and mixed a lot of different colors together. Neither Mickey nor Tim ever gave their side of the story in public to my knowledge, and other factors may have been involved. (Neither boy was proficient at dancing, and Mickey was a serious-faced lad who did not readily smile.) The brothers were replaced in early August 1955 by Ronnie Steiner, a professional tap dancer, and Dickie Dodd.
After leaving the show, Mickey attended Hollywood Professional School. He doesn't appear to have worked again until he turned seventeen, when he acted as host for a local television program called Andy Hardy Theater, introducing his father's old films. Mickey's main interests centered around music, both performing and songwriting. Though he would appear in several films during the next twenty years, it was usually as a musical performer. In 1963 Mickey played in a band comprised of students at the Hollywood Professional School, including Eddie Medora and Marty DiGiovanni, later of the Sunrays, John Walker of the Walker Brothers, Kathy Young, and Cubby O'Brien. They performed at "aud calls" (auditorium assemblies) for fellow students, an HPS tradition.
In 1965 he appeared in episodes of a Wonderful World of Color series called Further Adventures of Gallagher, which starred a former MMC talent winner, Roger Mobley. In 1967, Mickey was featured as lead singer for a rock combo in the cult classic Hot Rods to Hells (originally titled 52 Miles to Terror). Mickey then joined the surf group, the Sunrays, as a replacement in 1969, just as it was starting to break-up. He had a solo 45rpm released under the Capitol label, A Bone, A Dog, A Sword & A Shield/It Certainly Ain't A Nice Thing.
All during the late sixties Mickey was also playing with different bands, including some of his own. The latter included brother Tim and step-brothers Dan and David Kessel among the members. One of these groups, "Song", put out an album, appropriately titled Album, in 1970. This was also the year Mickey married Playboy Playmate Merci Montello, whom he met at the LA Playboy Club. Mickey had a part in a TV movie, Here There Be Dragons in 1975.
In 1978 Mickey put out a solo album on the AVI label called Crazy Ideas. Two of the songs from this were also released as a single 45rpm, Moonlite Masquerade/Crazy Ideas. Mickey has four songwriting credits on ASCAP, one with half-brother Ted Rooney, including Just A Friend,
and both sides of a 45rpm release on Liberty, The Choice is Yours/I'll Be There. Mickey also wrote some incidental music cues for a film he appeared in, Honeysuckle Rose (1980). That year also saw both Mickey and Tim performing on the televised Mouseketeer 25th Anniversary Show. Mickey finished up his acting career with a part in the film Songwriter in 1985.
In the late eighties Mickey married his third wife, Laura, to whom he remains married today. He formed "Rooney Brothers Entertainment Group" with brother Tim in the nineties, to produce music videos and films for commercial customers. Like his father, Mickey became a "born-again Christian", and now devotes his musical talents to writing and performing gospel music with his wife and their friend John Whittinghill.