[2] In 1983, Mahoney joined guitarist Kurt Habelt, drummer Rob Williams, and bassist Hank McNamee, all from nearby Weymouth, to form Siege.

[1] Siege played an extreme style of hardcore punk, combining exceptionally fast tempos with Mahoney's screeching and howling vocals.

Siege recorded a demo cassette and three tracks released on the Cleanse the Bacteria compilation, and performed throughout New England over the next few years.

The group is now cited as a catalyst of the grindcore and powerviolence genres, and has influenced such noteworthy bands as Napalm Death, Carcass, and Dropdead.

His play The Day God Moved to Scotland premiered with Catbox Cabaret at The Cantab Lounge Downstairs in 1993.

He would spend the next couple of years as one of their principle playwrights eventually stepping on the stage as an actor in the titular role in Doug O'Keefe's Sparky.