Jim was a police officer at Sky City until he quit his job on the force to pursue a career as a superhero. With support from his wife Donna, Jim became the Hornet and set out to become the world's first real-life superhero. Unfortunately, as he was about to leave the house on his first patrol, the news broke about the Plutonian's first public appearance.
Hornet was created by Mark Waid and Peter Krause and first appeared in Irredeemable #1.
Making his first appearance in the first issue of Irredeemable, Hornet also died within the space of it's first pages. He, and his family, were used as a device to showcase the brutality and ruthlessness of the titular "irredeemable" character the Plutonian. Most of Hornet's backstory was revealed in doses through flashbacks and selected dialogue throughout the course of the series.
Major Story Arcs
While trying to rescue a hostage wired to a bomb, Hornet's rescue attempt was interrupted by the Plutonian who made a mess of his stealth approach. Following Plutonian saving the hostage by throwing the bomb into space, Plutonian convinced Hornet to join him and meet up with a few other new superheroes which led to the formation of the Paradigm.
After Plutonian went insane and started killing his former team-mates, one of the first he targeted was Hornet. As Hornet rushed around trying to get his family to safety, the Plutonian arrived and incinerated Donna and his son. Hornet tried to save his daughter and convince Plutonian to spare her, Plutonian's reaction was to kill Hornet in front of his daughter and then taunt her before likewise killing her.