The Commando Cody character was first introduced in Republic's earlier serial Radar Men from the Moon. The odd choice of character name "Commando Cody" was possibly an attempt to make young audiences think they were going to see the adventures of Commander Corry, the hero of the ABC TV and radio series Space Patrol (1950–1955). The equally strange title Sky Marshal of the Universe was probably the studio's imitation of Corry's title, "Commander-in-Chief of the Space Patrol," proclaimed at the beginning of every Space Patrol radio and TV broadcast. There is, however, no concrete evidence this was ever a consideration by anyone at Republic Pictures.
Commando Cody was originally filmed as a twelve-part television series, but union contract issues forced Republic to first exhibit it through regular movie theaters as a 12-part weekly serial. While the TV episodes build on each other in chronological order, the serial episodes lacked the traditional cliffhanger endings that characterized all previous serials.
The Sky Marshal TV series is a prequel to the Radar Men from the Moon theatrical serial. The first episode has characters Joan and Ted, Commando Cody's established sidekicks in Radar Men, applying for their jobs and meeting Cody for the first time.
There was a substantial break between filming the first three and last nine episodes of the TV series, during which time Republic set about filming a new Rocket Man movie serial called Zombies of the Stratosphere, also starring Judd Holdren and Aline Towne. Originally intended to be a Cody serial, and a direct sequel to Radar Men, Zombies was subject to last-minute revisions to its principal characters; most notably Holdren's "Commando Cody" character became "Larry Martin" instead. Meanwhile, the third TV episode was filmed in a way to show the apparent death of The Ruler, suggesting that Republic may have reconsidered filming the remaining nine TV episodes by converting the three it had finished into a regular science fiction feature film.
By the time work finally resumed on the Sky Marshal series, Republic had lost actor William Schallert as Cody's male colleague "Ted Richards" (played by William Bakewell in Radar Men). A replacement was found in Richard Crane, a year before his best-remembered role as the title character on the science fiction TV series Rocky Jones, Space Ranger. The Ruler also gained a female sidekick, played by Gloria Pall, though she had almost no screen dialog.
In each episode The Ruler tries to take over the Earth with a new scheme, each one designed to make maximum use of Republic's stock footage library of various disasters and previously used action long shots. For the series, a number of new outer space scenes were filmed that had not been seen before in Republic serials, including "space walks" for several exterior spaceship repairs; aerial raygun duels between "hero" and "enemy" spaceships; and black star fields (rather than daylight and cloud-spotted skies) for backgrounds when Cody's or the villain's spaceships were shown outside the Earth's atmosphere.
Cody and his associates use special badges that conceal radios to communicate with one another, prefiguring similar communication badges used more than 30 years later in Star Trek: The Next Generation. There were futuristic props and sets, as well as shots of the intricate model-rocket special effects work of Republic's Howard and Theodore Lydecker; the spaceships of Cody and The Ruler are the same basic shooting miniature with different attachments and markings added to make them appear different
Judd Holdren as Commando Cody
Aline Towne as Joan Gilbert. (Towne was the only performer from Radar Men from the Moon to reprise her role.)
Gregory Gaye as The Ruler
Lyle Talbot as Baylor (six episodes)
Craig Kelly as Mr. Henderson