Circus Boy is Micky's first TV Series (1956-1958). He's billed as Micky Braddock. His costar is Noah Beery Jr.
Episode One Commentary-link
Episode Two Commentary-link
"Meet Circus Boy" is Episode 1 (Pilot), from the First Season.
"The Fabulous Colonel Jack" is Episode 2 from the First Season.
"Micky Dolenz Sings in Circus Boy" is a clip of the entire cast singing the Theme Song ("It's great, it's terrific, it's the best show on Earth!!") and Micky has a few featured lines. The group seems to be obviously singing along to a record, which was common practice for shooting film, even in the 1950's.