|“||Don't profile me, Aaron.||”|
— Sean in "The Tribe"
Very little is specified about Sean's past, other than he was born sometime during 1981 and had a dream of becoming a lawyer, much like his older brother. He and Hotch barely interacted with each other as children, since the latter had gone to boarding school by the time Sean was entering the first grade. As a result, the two of them became estranged. He planned to study law in Georgetown University, but sometime prior to "The Tribe", he changed his mind for unknown reasons and instead decided to become a frycook at a restaurant in New York.
In the beginning of the episode, Sean tells Hotch his change of plans at the BAU headquarters, but is met with disapproval. The two have a brief argument and Sean leaves. At the end of the episode, Hotch meets up with Sean at the restaurant he is now working at, and he tells him that he realizes that Sean should handle life his own way. The two make amends and Hotch decides to purchase some food from Sean.
Prior to "Brothers Hotchner", Sean had lost his job at the restaurant and got a job as a bartender in a New York City bar called the Edinburgh, where he currently works. After witnessing the death of Anna, a barfly, which is cited as an apparent overdose on ecstasy, he calls Hotch, who is in Manhattan on vacation with Jack and Beth because he believes the death to be suspicious due to the bleeding from her eyes, nose, and mouth, as well as the fact that the manager wasn't willing to call 911 for some time after the death. He tells Hotch about Linda Heiying, who had also apparently overdosed, but who he was sure was not using because he had a relationship with her. Hotch promptly calls the rest of the team over to New York.
Sean later reveals to Rossi that he was using ecstasy while he was dating Linda, but she had convinced him to get clean and he had not used it in two months. He had been getting the drugs from Thane Parks, his boss at the bar who gave him the job in the first place, who would date-rape women at the bar using ecstasy-tainted wine. He then volunteers to try and wrangle information about the drugs from Thane by wearing a wire. While undercover, he lies to Thane to earn his trust. Falling for the trick, he takes him down to the storeroom so that he can help him dump the tainted wine. When Thane admits to spiking it after discovering that one of the cases is taken by Sean (unbeknownst to Thane), Sean accuses him of killing Linda and assaults him. Hotch and Morgan intervene just in time to prevent Sean from getting stabbed by Thane. Sean goes outside, texts an apology to Hotch, and flees.
Later, Sean calls Hotch from a payphone; Hotch tries to convince him to come back, as it appears that the unsub was targeting employees of the Edinburgh after the bar's owner, Jim Peters, is killed. Sean tells him to solve the case, to which he will then finally come back. After the case is solved and the killer is arrested, Sean shows up at Hotch's hotel room, meeting Beth and seeing Jack for the first time in four years. He admits that the missing case of wine was his fault, and that he had sold it to pay rent. Hotch tells him that they need to do better; Sean agrees, and acknowledges that he needs to own up to his mistakes, stating his knowledge that he will have to face charges for assaulting Thane and then fleeing the scene. He then asks Hotch if he knows any good lawyers. Police officers then take Sean into custody, but not before he and Hotch shake hands.
- Sean is nicknamed "Hotch", just like his brother, except he hated the nickname likely because it reminded him of his difficult relationship (or lack of one) with Hotch.
- ↑ Hotch states that Sean is 25 years old at the time of The Tribe