As a comic book writer, Jensen worked with creator/artist Phil Avelli [2] on the independently published black-and-white comic book Leaf (1991). There were only two issues.

In late 1993, Marv Wolfman left writing Team Titans to focus more on New Titans and Deathstroke.[3] Jensen and co-writer Phil Jimenez took over, writing Team Titans #13 (October 1993) to Team Titans #24 (September 1994) and the Team Titans Annual #2 (1994). It was then cancelled.

Jensen wrote the four-issue X Factor miniseries (2002) and contributed two short stories to Captain America: Red White and Blue (September 2002). His other short story work includes a piece drawn by David Lopez for IDW Publishing’s anthology ＂Love Is Love: A Comic Book Anthology to Benefit the Survivors of the Orlando Pulse Shooting＂ (2016), and a collaboration with artist Jared Cullum for the Boom! Studios anthology ＂Planet of the Apes: When Worlds Collide＂ (2019).

Jensen wrote the hardcover black-and-white graphic novel Green River Killer: A True Detective Story (Dark Horse; September 2011), which was penciled and inked by artist Jonathan Case and lettered by Nate ＂Blambot!＂ Piekos. It detailed the Green River Killer case from the point of view of King County Sheriff’s Office detective Tom Jensen, the author’s father.[4] It won the Eisner Award for Best Reality Based Work in 2012.

His first prose novel, Before Tomorrowland, a prequel to the film co-written with Case, was released on April 7, 2015.