Sam Katzman was well known for being able to get a fad (which rock and roll was considered to be at the time) to the big screen before the fad had faded away and also for being able to do it on the cheap. He is often criticized that a lot of the movies he produced had weak plots and bad acting. I personally think everyone owes him a debt of gratitude for capturing some of the early rockers and rhythm and blues singers on celluloid. Rock Around The Clock was Katzman's first music exploitation movie and after the success of Rock Around The Clock, he produced more music exploitation movies using "rock and roll" (Don't Knock The Rock, Jukebox Rhythm, Get Yourself A College Girl), "calypso" (Calypso Heat Wave), "the twist" (Twist Around The Clock, Don't Knock The Twist), "folk music" (Hootenanny Hoot), "British Invasion" (Hold On with Herman's Hermits) and even a couple of Elvis Presley movies (Kissin' Cousins, Harum Scarum).
Rock Around The Clock is generally considered the first rock exploitation movie by Katzman or anyone else. It was made to capitalize on the success that the song,"Rock Around The Clock" had received as part of the soundtrack in the movie Blackboard Jungle. Although it's hard for us today to look at Haley and see a "rock and roll" performer, he was huge during the years of 1954-56. Around 1957 his popularity declined when Elvis and other artists came along, who not only "looked like rockers" but also seemed to have "rock and roll" embedded within themselves.
Rock Around The Clock's plot revolves around the birth of "rock and roll" and points you to Bill Haley as the originator of the sound. While we all know that's not true, the plot of the movie can only exist by accepting that premise. Steve Hollis (Johnny Johnston) tells members of a Big Band that he has been representing that "big band music" is washed up. The band fires him, after which Steve and one member of the band, Corny (Henry Slate), decide to drive to New York. Along the way they stop in a small town where they find the town listening and dancing to Bill Haley and His Comets. They can't figure out what type music they are listening to "since it isn't boogie, it isn't jive and it isn't swing, it's sort of a combination of all of them". Once they find out it's a music called "rock and roll" Steve sees the next big thing and wants to sign the band plus a brother/sister dancing duo (who will be required to show kids how to dance to "rock and roll").
The rest of Rock Around The Clock revolves around getting the band and dancers signed and onto a national stage. There's a subplot about a romance between Steve and the female dancer (Lisa Gaye) that causes some trouble with a big booking agent whose daughter (Alix Talton) wants to marry Steve. Once Steve finds out that they have been blackballed by the booking agent, he turns to an old friend, Alan Freed, to help them get a foothold on entertainment bookings and of course everything works out fine by the end of the movie.
Rock Around The Clock not only had performances throughout the movie by Bill Haley and The Comets, who it appeared did have a pretty good rockin' stage show, but also The Platters who sing "Only You" and "The Great Pretender", Tony Martinez and his band do four Latin numbers, and Freddie Bell and His Bellboys sing "We're Gonna Teach You To Rock" and "Giddy Up Ding Dong".
A last note about Freddie Bell and His Bellboys, they recorded a version of "Hound Dog" in 1955 and in 1956 Elvis (who was doing a not very successful Las Vegas appearance at the time) saw Freddie Bell and His Bellboys singing it in their Las Vegas show and was moved to record it himself. This is interesting to me on two levels: Freddie Bell and his group have always looked more like a lounge act than a "rock and roll" act to me, and also the fact that Elvis would eventually wind up many years later in Las Vegas singing "Hound Dog", the song that he had "discovered" there and made famous.