Not much is known about where Jett came from or his past. He does exhibit multiple accents, usually Cockney or London British, although after strenuous shapeshifting or other activities he sounds closer to Russian. Before he began adventuring with the party, he was a musician. Whether he was actually popular or not is up for interpretation.
Jett Razor is often depicted with a mohawk and modern "Rock and Roll" clothing. As a changeling, his true form is unknown.