Jason Gideon

Jason Gideon is a criminal profiler who is formerly the Senior Supervisory Special Agent of the FBI's Behavioral Analysis Unit. The position is now held by David Rossi (Joe Mantegna).

Background
Gideon had reportedly suffered a nervous breakdown due to the death of six of his colleagues in a warehouse bombing before the beginning of the series. He was called back from medical leave in the pilot episode, "Extreme Aggressor". Upon his return, he was reinstated as Unit Chief but later stepped down and allowed Hotch to take his place. He would then become Senior Supervisory Special Agent until his departure in Season Three.

Gideon has a knack for counseling his colleagues and has been a great help to both Derek Morgan and Spencer Reid. He is also an avid chess player, shown playing with--and beating--Dr. Reid on several occasions.

He had a relationship with a woman named Sarah Jacobs, who would later become a victim of Frank Breitkopf.

On the Job
After a series of emotional cases, one of which resulted in the death of his girlfriend, Gideon began feeling very burned out. The last straw was Hotchner's two-week suspension, for which Gideon felt responsible. He retreated to his cabin during the suspension and left a letter for Reid, who he knew would be the one to come looking for him.

When Reid arrived at the cabin, it was empty except for the letter and Gideon's badge and weapon. Gideon was last seen remarking to a Nevada diner waitress that he didn't know where he was going or how he'd know when he got there, leaving the diner and subsequently driving off in his vehicle. He also mentioned that one of his reasons for resigning from the BAU was to regain belief in himself and happy endings.