Dario Lombardo, a 25-year-old from Messina, was named by Spanish authorities on Friday, Il Sole 24 Ore newspaper reported.
Although Sicilian, Lombardo had been living with his parents in Germany.
DNA tests are expected to confirm his identity later today.
A further 178 people were injured in the crash after the express train jumped its rails and was ripped in half. The accident happened in the region of Galicia.
The train driver admitted on Thursday that he was going twice over the legal speed limit of 80kph.
The disaster is the worst railway crash in Spain since 1944.