D’Amour left Tool in 1995. According to Danny Carey, D’Amour left the band because he wanted to play guitar rather than bass. In 2020, D’Amour explained that being in Tool felt limiting and the creative process was “excruciating and tedious.” After his departure from the band, he formed the psychedelic pop band Lusk with Brad Laner, Chris Pitman, future member of Guns N’ Roses, and Greg Edwards of Failure and Autolux. In 1997, they released their only album, entitled Free Mars.

Soon after his departure from Tool, D’Amour played guitar in a group named Replicants, a cover band that included Ken Andrews and Greg Edwards from Failure, as well as Chris Pitman. They released one self-titled album in 1995, with a guest appearance from former Tool bandmate Maynard James Keenan.

As of early 2005, D’Amour has been writing and performing under the name Feersum Ennjin. The name is inspired by the science fiction novel Feersum Endjinn by Iain Banks, an author whose novel The Wasp Factory was conceptual inspiration for Lusk as well. The project released a self-titled EP on Silent Uproar Records. In 2011, a self-titled LP was released on Dissociated Press, featuring some songs that had been released previously and some new ones. On the first track of the LP, “The Fourth”, former Tool band-mate Danny Carey plays drums.

Currently, D’Amour plays bass in the band Lesser Key. The group consists of Andrew Zamudio (vocals), Brett Fanger (guitar), and Justin Hanson (drums). The band “represents an exploration into personal and artistic freedom.” On July 26, 2013, the band released a video of their debut single “Intercession.” Their debut EP was produced by former Tool producer Sylvia Massy and released on April 1, 2014 on Sumerian Records.