Initially, Johnny Cage was a struggling Hollywood action movie star who sought to revitalize his career and reputation. He entered the Mortal Kombat tournament for the sole purpose of displaying his fighting skills and proving himself to skeptical film critics, as they believed Cage was nothing more than an actor who relied too much on stunts and camera work, and was not really a proficient fighter. Eventually, he would become one of the most important defenders of Earthrealm. Despite his materialism, airheadedness, and occasional immaturity, Cage is a brave and loyal warrior, although his antics frequently annoy his allies. For this reason, fans consider him to be the series' foremost comic relief character.

Johnny matures considerably by the time of Mortal Kombat X, losing much of his earlier arrogance and airheadedness. In the process, he becomes a more rounded and serious character, although his penchant for humor remains mostly intact. He maintains this persona in Mortal Kombat 11, complemented by the additional presence of his past self, who shares his former cockiness and brash traits.