In 2011, he had a falling-out with Rizzuto mobster Raynald Desjardins, and on November 24, 2011, his body was found on the shore of Île Vaudry on the L'Assomption River, in the city of Charlemagne, Quebec.

During the late 1990s, Montagna's name was overheard in wiretapped conversations between Boss Joseph "Big Joe" Massino and other reputed members of the Bonanno crime family.

He started a small metalworking company called Matrix Steel Co., located at 50 Bogart Street in Bushwick, Brooklyn, managed by his wife.

[5] In late 2003, US law enforcement and the Federal Bureau of Investigation (FBI) listed Montagna as an "Acting Capo" and Caporegime of the Bonanno family on behalf of DeFilippo and the Sicilian faction based in the Bronx.

[5][11] The 2003 criminal contempt conviction allowed U.S. authorities to strip him of his greencard and deport him to Canada; he was succeeded by Vincent Badalamenti as Bonanno family boss.

According to mob writer Jerry Capeci, it was understood Montagna would have no standing or authority within Montreal's then-dominant Rizzuto crime family.

[19][20] Law enforcement believed that Montagna was brought to the house of convicted smuggler Jack Arthur Simpson, as his vehicle was later found parked on a Montreal street.

[22] The police investigation confirmed that Raynald Desjardins had taken part in the plot to murder Montagna,[23] who, at the time, was suspected of trying to shake down Montreal-area construction companies, due to their alliance with the Rizzuto family.

[28] Montagna was portrayed by Joris Jarsky in the television drama series Bad Blood, which debuted in 2017, surrounding the Rizzuto crime family.