Massimo never wished to join the Rebellion; he did so out of the necessity of escaping his hidden, troubled past long enough to find a new world to settle on. After being caught up in the war with the Galactic Empire, he decided to make the most of his situation.
When the former Emperor's Royal Guardsman Kir Kanos found his way to Phaeda and to Sinn via Tem Merkon, Massimo was initially wary of whether they could trust Kanos, whose loyalties were to the deceased Palpatine.
Before Sinn's acceptance of Kanos after he nearly single-handedly saved them from Colonel Shev's forces, Massimo threatened to take over Sinn's command. Sinn questioned whether that would make him any different from the Galactic Empire against whom they were fighting.
Although Massimo believed Kanos to be the traitor who informed Shev of their whereabouts, the guilty member was none other than Merkon. When Merkon returned to Sinn's base after secretly meeting with Carnor Jax, Massimo killed him.
Upon the arrival of General Wedge Antilles aboard the Lusankya, Kanos went to Yinchorr, knowing Jax would follow. Sinn and Sadeet also followed, hoping to aid Kanos in his fight against Jax, and Massimo was left to oversee operations on Phaeda.
Aboard the Lusankya, Massimo told Antilles about his previous desire to take over from Sinn and expressed his sincerest apology and newfound loyalty to Sinn and the New Republic.
When Mirith Sinn infiltrated the court of Grappa the Hutt on Genon, however, Massimo betrayed her and the New Republic by revealing to Grappa that Sinn was spying on him. Grappa rewarded Massimo by giving both him and Mirith to Zzzanmxl and the Zanibar.
The Zanibar brought Massimo and Mirith Sinn to the Zanibar homeworld of Xo where planned on slaughtering the two in a bizarre religious ceremony. Although believed dead, Massimo actually escaped his fate, his prisoner rack having been hit by a stray blaster bolt during Kanos' escape from Zzzanmx. The falling rack knocked Massimo onto a bed of burning coals. Due to his burns and scars, he replaced his right arm and half his face with cybernetics.
Desperate for revenge, he attempted to kill Kanos by luring the former guardsman into a trap, by bribing a magistrate to offer Kanos a fictive bounty on his own head. When Kanos arrived to Massimo's stronghold, he was attacked by the security droids, but managed to evade them and kill Massimo.
He was voiced by Peter Thoemke in the audio drama version of Crimson Empire.