Special Agent Aaron "Hotch" Hotchner (Thomas Gibson) is the unit chief of the Behavioral Analysis Unit (BAU) for the FBI. Hotchner is a former prosecutor and was transferred to the unit from Seattle. Hotch is one of the most experienced and dedicated agents in the unit, a borderline workaholic, and has his home life disrupted by his work. He is the sober, serious leader of the BAU and has a reputation for professionalism as well as a commitment to justice.
Hotchner married his high school sweetheart, Haley Brooks Hotchner (Meredith Monroe), and the marriage produced a son named Jack (Cade Owens). After a lot of disagreements over his work, Hotchner requested a transfer to a different division to please his wife. Derek Morgan (Shemar Moore) convinces him to stay and help with a case in Milwaukee, and Hotchner withdraws his request. When Haley finds out that Hotch changed his mind about the transfer, she takes Jack and leaves him. He is served with divorce papers while he is a work. Hotch does his best to maintain a good relationship with Jack, and, although he remains in love with his wife, he is dissatisfied with the arrangements.
Some time after their divorce, Hotch is profiling a case in Boston, and the killer, George Foyet (C. Thomas Howell), known as the Boston Reaper, shows up at his apartment. Foyet stabs Hotch nine times and then leaves him in the emergency room at St. Sebastians Hospital. Hotch survives the stabbing only to discover that Foyet has taken Haley's address from his apartment - requiring that she and Jack go into protective custody until he is captured. During this time, Hotch can have no contact with Haley or Jack. With Hotch recovering from the attack and isolated from his family, he steps down as unit chief due to pressure from within and appoints Derek Morgan to act as chief in his absence.
Unable to resist the urge, Foyet begins to toy with Hotch. Posing as a U.S Marshall, Foyet is able to find Haley and breaks into her home. Foyet then has Haley call Hotch, who is forced to listen to her being murdered over the phone but at least is able to tell Jack to help him "work the case." This is a code phrase telling Jack to hide in a secret place in the house so that he will be safe. Hotch immediately rushes to Haley's home. When he arrives at the house he finds Haley's murdered body and notices Foyet trying to hide behind the curtains. Hotch attacks, and, during the fight that ensues, Foyet tries to surrender. Hotch, certain that Foyet will try to kill his son, continues to beat him until he is dead. The rest of the unit finally arrives and convinces Hotch to stop beating the dead body.
Hotchner is reviewed following the incident, but is cleared after it is determined that his actions were justified. The bureau offers him a full retirement package so he can raise his son, but Haley's sister, Jessica (Molly Baker), offers to stay with Jack when Hotch has to be out of town, so he assumes his position as unit chief of the BAU and attempts to build a new life with his son.
"I don't have to think; I know that he would have tried to kill my son too."
"...some people grow up to become killers... and some people grow up to catch them."