Mario Brunetta was chosen in ht eighth round, 162nd overall by the Quebec Nordiques in the 1985 NHL Entry Draft. Brunetta played three years of major junior hockey in the QMJHL, beginning in 1984-85, playing 45 with the Quebec Remparts. He complied a 20-21-1 record with a 5.11 gaa in the offensive-minded league. In 1985-86, Brunetta joined the Laval Titan, starting 63 games as the club's number one netminder. In his final year of junior with the Titan in 1986-87, Brunetta played in 59 games, securing one shutout and a 4.51 gaa.
In 1987-88, Brunetta turned pro with the Fredericton Express of the AHL. He began the year with an impressive 4-1-0 mark and was called up to the Nordiques, where he played 29 games. He had an official 10-12-1 record with a 3.72 gaa. The following year he played in just five games with Quebec, sporting a 5.04 gaa while going 1-2-0. The balance of the year was spent with the AHL's Halifax Citadels. Brunetta appeared in six more games for the Nordiques in 1989-90, which turned out to be the final games of his NHL career. Again, the balance of his season was spent in Halifax with the Citadels.
Brunetta was released by the Nordiques and was unable to generate interest from other NHL teams, so he packed up and moved to Italy where he joined the Asiago club of the Italian Elite League. He played there for two years before moving on to Milan for another two years. In 1996-97, Brunetta signed with the Berlin Polar Bears of the DEL where he was the team's top goaltender for three years. In 1999-00 he played 50 games in Sweden for Vastra Frolunda HC Goteborg. Brunetta returned to Germany in 2000-01 to play for Ingolstadt.