At Marvel Tieri has written New Excalibur, Iron Man, Wolverine (and its spin-off, a short-lived Weapon X ongoing series), Underworld, a post Avengers Disassembled Hercules mini-series, Wolverine/Darkness, X-Men: Dracula vs. Apocalypse, Civil War: War Crimes, as well as World War Hulk: Gamma Corps for Marvel Comics.

For DC, he has written a JSA Classified story, as well as Countdown tie-ins Lord Havok and the Extremists, Gotham Underground, and two upcoming issues of Batman and the Outsiders.

His style is gritty, yet usually laden with pop-culture references and black humor, and as such has kept on writing the books spotlighting villains. Tieri was recently announced to be the writer of the storyline in the upcoming Fate of Two Worlds.

He appeared at the MarvelFest NYC 2009 event along with other writers Dan Slott and Chris Claremont and comedic writer Scott Adsit.

Comics work includes:

Marvel Comics

• Deadpool
• New Excalibur
• Iron Man
• Wolverine
• Weapon X
• Underworld
• Hercules
• Wolverine/Darkness
• X-Men: Dracula vs. Apocalypse
• Civil War: War Crimes
• World War Hulk: Gamma Corps

DC Comics

• JSA Classified
• Lord Havok and the Extremists (with Liam Sharp, 6-issue limited series)
• Gotham Underground (with pencils by Jim Califiore and inks by Jack Purcell, 9-issue mini-series, 2007—2008)
• Batman and the Outsiders
• Gotham Underground
• Lord Havok And The Extremists