Dysart co-created and wrote Violent Messiahs in 1997. The first eight issues, collected in the graphic novel Violent Messiahs Vol. I: Book of Job in 2002, were nominated for the Harvey Award, the Wizard Fan Award, and the Eisner's Russ Manning Award. The last four issues, a story arc entitled "Lamenting Pain", was not collected until 2009, when IDW Press decided to publish a trade which also featured never before seen developmental material and an unseen short story by Dysart.
More work followed, including a two-year stint as the monthly writer of Swamp Thing, writing issues #9–29 of the fourth series. His run featured the art of Enrique Breccia and Richard Corben (among others) on interiors and John Totleben and Eric Powell on covers. Dysart has also worked on Conan and Hellboy and has co-written with Mike Mignola on a series of projects in the same setting of Hellboy.
From 2008 to 2010 he wrote a revamp of The Unknown Soldier for Vertigo. The storyline took place in Acholiland, Uganda, in 2002 during the war between the Lord's Resistance Army and Ugandan People's Defence Force. Dysart spent a month in Northern Uganda for research. Issue #1 of Unknown Soldier was released in October 2008. The book was a monthly. It was nominated for an Eisner Award for Best New Series in 2009. and won a Glyph Comics Awards for Best cover. In 2010 Unknown Soldier won the Glyph for STORY OF THE YEAR. Unknown Soldier was featured on the front page of the art section of the New York Times and Dysart was interviewed by the BBC, who also published some of his research photos on their website. In December 2009 Dysart gave an exhaustive interview to WORLD VISION REPORT about his experiences in the conflict zone and attempts to adapt them into a mainstream, commercial work.
In June 2010, Vertigo Comics published Dysart's graphic novel based on Neil Young's 2003 album Greendale. Cliff Chiang drew the book. It spent two weeks at #3 on the New York Times Graphic Novel Best-Seller list.
In 2012 Joshua Dysart became one of the primary architects of the Valiant Universe when he helped launch the "Summer of Valiant" with fellow creators Robert Vinditti, Duane Swierzinski, Fred Van Lente, and Justin Jordan. It was a reboot of the shared superhero universe of 1990's era publisher Valiant Comics. He has since done two monthly series, the revamp of Harbinger and the original Imperium, and co-wrote Bloodshot for the publisher, as well as multiple single issues over the years. He and artist Khari Evans are responsible for bringing back the popular Faith/Zephyr character, an overweight female superhero, in her current incarnation. In 2013 he helmed Valiant's first summer crossover, Harbinger wars, which introduced his original creation, a team of super-powered children called Generation Zero. Generation Zero and Faith were both given their own individual series.
In 2015 the World Food Programme released Living Level-3: Iraq by Dysart, Alberto Ponticelli, Pat Masioni, and Thomas Mauer. For the work Dysart once again went to a war zone, traveling across northern Iraq in 2014 to interview Syrians, Yazidis, Kurds, and Arabic Christians who were fleeing both the Syrian Conflict and the rise of Da'esh. The work was first published, free to read, on Huffington Post World in four installments. In 2017 WFP released Living Level-3: South Sudan, the sequel by Dysart and the same team. Again, Dysart spent ten days traveling in the subject country for research.
Dysart has been extensively involved in multi-media crossovers over his career. He authored the one-shot Van Helsing: Beneath the Rue Morgue (an original story featuring the character from the Universal film) and penned Skull & Bones: A Monster House Story, which was tied into the Sony animated children's Monster House. He's also had his comic books included in the packaging for both the Age of Conan: Hyborian Adventures MMO computer game from Funcom and the Hellboy video game from Konami. He has written a two-volume 270 page graphic novel for Avril Lavigne entitled Make 5 Wishes which was published by Del Rey Manga and Random House. That book has been printed in over seven languages as well as digitally distributed throughout Asia. His six-issue comic book mini-series adaptation of the Deepak Chopra novel Buddha: A Story of Enlightenment was published in December 2010.
in 2015 Valiant Entertainment announced a five-picture deal with Sony Pictures to bring two of its series Bloodshot and Dysart's Harbinger, to the big screen. Both Bloodshot and Harbinger will receive two features each before a fifth movie, Harbinger Wars, also written by Dysart, is hoped to be released.
Dysart has, on multiple occasions, taught and talked about the role of comics in pop-culture, as well as actively promoted comics "he feels bring a wider audience to the medium". He has produced discussion panels for the West Hollywood Book Fair in 2006 and moderated in 2007' as well as written about the virtue of comics for the LA Weekly. In 2008 and 2009 he was a special guest at Ohio University's Aesthetics Technology Lab and even wrote a short comic story about his experiences there that featured the art of Ronald Wimberly. That story, called THE STAIN, was a Best American Comics of 2010 notable entry. In 2009 Dysart spoke at the University of Miami on his experiences writing the Unknown Soldier. That same year he interviewed Bryan Lee O'Malley on Scott Pilgrim vs. The World. In 2010 he interviewed David Petersen on his Eisner-award winning Mouse Guard comic.