Thibert broke into comics in 1986, as an inker for WaRP Graphics' Myth Adventures. He truly latched on to the industry in 1989, becoming regular inker (over Dan Jurgens' pencils) for DC's The Adventures of Superman until 1991.
From 1991–2004 (with a break from 1993–1995), Thibert inked almost exclusively for Marvel, many of those years spent on their X-Men titles. He inked X-Factor for much of 1991, and was the regular inker of X-Men vol. 2 in 1992.
From 1993–1995, Thibert associated himself with the "upstart" Image Comics, where he primarily inked covers, for such titles as Spawn, Supreme, Team Youngblood, and Brigade.
Returning to Marvel, Thibert inked Carlos Pacheco on X-Men vol. 2 from 1996–1998. He also returned to X-Factor in 1997. In addition, during the 1990s Thibert inked over twenty issues of The Uncanny X-Men. From 1999–2000, Thibert inked virtually the entire run of Bishop: The Last X-Man (over penciller Georges Jeanty). He was the regular inker of Ultimate X-Men in 2001 (over Adam Kubert), and again from 2003–2004 (over David Finch).