Salvatori wrote music for his own rock band while he was in college, and became friends with Martin O'Donnell. O'Donnell eventually moved to Chicago after completing his degrees, and was approached with a job offer to score a colleague's film. Since Salvatori had his own recording studio, O'Donnell offered to split the job with him; the two became partners.
Soon after producing the music for Myth II, Bungie contracted O'Donnell for several of Bungie's other projects, including the third-person game Oni. Bungie wanted to re-negotiate the contracts for Oni in 1999, which resulted in O'Donnell joining the Bungie team ten days before the company was bought by Microsoft. Salvatori remained behind to manage the business aspect of TotalAudio, which he continues to do.
O'Donnell and Salvatori's company TotalAudio was contracted to produce the music for Bungie's upcoming title, Halo: Combat Evolved. During production Bungie decided that instead of contracting work to O'Donnell, they would hire him. Salvatori remained at TotalAudio to manage the business aspect of the company, and shortly after O'Donnell joined the team, Bungie was bought by Microsoft. Salvatori co-composed the music for Halo's sequels—Halo 2 and Halo 3—with O'Donnell, who has called Salvatori one of his musical influences.
For the music to Halo 3: ODST, O'Donnell began work on crafting the game's themes before Salvatori joined the team in February 2009. "Marty [O'Donnell] had started writing before me, and sent me some of his ideas," Salvatori said. "I picked a few that I felt I could add some magic to, and worked on those. I also came up with several ideas that I sent to Marty that he put his hands on." Once the duo felt they had enough material, the Chicago-based Salvatori flew to Bungie in Seattle to complete the arrangements and record live musicians.
Early on, the team decided that rather than rely on old Halo themes, ODST would feature all-new music. "It was a bit intimidating at first," Salvatori recalled, "because in previous Halo games if new ideas weren't coming, I could always dust off an old one and give it a new spin. I was afraid that we might hit some writer's block along the way, but that didn't happen at all. Instead, we had the freedom to explore some new musical territory, and the ideas flowed pretty quickly." With the exception of the main player character, O'Donnell and Salvatori did not compose themes to represent characters. While the game's setting in Africa inspired some percussion pieces, the team was interested in a sparser atmosphere, which Salvatori described as "a bit darker and less epic".
He most recently co-composed the soundtrack to the 2014 video game, Destiny for which he won the 2014 Original Dramatic Score, New IP by National Academy of Video Game Trade Reviewers (NAVGTR).
O'Donnell and Salvatori's music has been packaged and released in physical and digital forms. The soundtracks feature "frozen" arrangements that represent an approximation of a play-through of the games. The Halo Original Soundtrack sold over 40,000 copies, and was followed by two different releases of the music to Halo 2. The two volumes of the Halo 2 Original Soundtrack were produced by Nile Rodgers, with the first album being released in sync with the video game in 2004 and became the best-selling game soundtrack of all time. The second album was released more than a year after the soundtrack had been mixed and mastered. Halo 3's soundtrack was released in November 2007, and featured a fan contribution that was the select winner from a pool of entries judged by O'Donnell, Rodgers, and others. All of Salvatori's contemporary work on the series was repackaged as Halo Trilogy—The Complete Original Soundtracks in December 2008, alongside preview tracks written by Halo Wars composer Stephen Rippy. The music for ODST was released in a two-disc set on September 22, 2009.
Salvatori continues to engineer, produce and compose his own music. Aside from Halo and Destiny, he has served as the audio lead and composer for Stubbs the Zombie. He also created the music for Disney's Guilty Party.