He participated in 29 Formula One Grands Prix, debuting on 29 May 1994 for Simtek, replacing Roland Ratzenberger, who had been killed during qualifying for the 1994 San Marino Grand Prix. Montermini himself crashed heavily in practice for the 1994 Spanish Grand Prix, breaking his left heel and his right foot. He returned to Formula One the next season, with the Pacific Grand Prix team, and drove for Forti in 1996 alongside countryman Luca Badoer until the team folded. Montermini was also rumoured to become a test driver for the MasterCard Lola team, but it folded after one race in 1997. He scored no points in his Formula One career.