He was born in Los Angeles, California the son of George Michael Dolenz, a Hollywood character actor, and his wife Janelle Johnson. Dolenz began his show business career in 1956 when he starred in a children’s show called Circus Boy under the name Micky Braddock. In the show he played an orphaned boy who is the water boy for the elephants in his uncle’s one-ring circus at the turn of the 20th Century. The program ran for three years, after which Dolenz made sporadic appearances on network TV shows and pursued his education. He also played with a couple of obscure rock and roll bands, including one called The Missing Links.

In 1965 Dolenz was cast in the television sitcom The Monkees and became the drummer and lead vocalist for the band created for the show. He wrote a few of the band’s songs as well as providing the lead vocals for such hits as “Last Train to Clarksville” and “I’m a Believer”. Toward the end of the series’ two-year run Dolenz directed and co-wrote what turned out to be the show’s final episode.

While in the UK on tour with the group, Dolenz met and married Samantha Juste, the girl who pretended to put the records on the jukebox on the BBC's "live" pop series, Top of the Pops. Daughter Ami Dolenz, now an actress, was born in 1969; Dolenz and Juste divorced in 1975.

After the show ended and the band broke up, Dolenz provided voice-overs for a number of Saturday-morning cartoon series. He also auditioned for the role of Fonzie on the series Happy Days, but lost out to Henry Winkler. He eventually reunited with fellow Monkee Davy Jones and songwriters Tommy Boyce and Bobby Hart for a record and a tour, but he had bigger success with a stage production of the Harry Nilsson musical The Point! in London.

After the show’s run, he remained in England and began directing for the stage and television, as well as producing several of the shows he directed. He has since joined the other ex-Monkees for reunion tours and has continued to direct for television both in England and in the United States.

While Tim Burton was still slated to direct Batman Forever, Micky was considered to play The Riddler, and even did a screen test for the role. However, Burton's exit from the film ended Micky's involvement. (An ironic footnote is that "Circus Boy" co-starred Robert Lowery, who played Batman in the 1949 Columbia serial Batman And Robin.) Not to be left out of the Batman franchise completely, Dolenz, as a voice actor, played Two-Face's twin henchmen in the two-part episode "Two-Face" on Batman: The Animated Series.

In 2005 Dolenz replaced Harry Harrison as the morning disc jockey at oldies radio station WCBS-FM in New York. On June 3, 2005, Micky celebrated his 100th show with a special morning show at B.B. Kings. At 5:00 PM, WCBS-FM announced that the station would replace its oldies format with a "Jack" format. Micky went on tour with his sister, singer Coco Dolenz.