Sean Hillinger on Day 7
|Portrayed by||Rhys Coiro|
|First appearance||Day 7: 8:00 AM – 9:00 AM|
|Last appearance||Day 7: 5:00 PM – 6:00 PM|
 Day 7
After Jack Bauer was brought into FBI HQ by Renee Walker, Janis Gold asked Sean to clear Jack for entry. Sean was hesitant to do so and argued with Janis, but he eventually did his job. Agent Moss then had Jack sit with Sean so they could work together on figuring out how Tony Almeida survived after his death at CTU and his reason for helping out the terrorists.
After Tony nearly crashed two planes into each other as a warning to President Taylor, Sean began to worry about his wife Christina who was arriving back in the city aboard a plane. He then posed as Larry Moss and used his higher authority to instruct Air Traffic Control to make her plane a priority landing. Sean then called his wife and told her that everything would be okay, but that he wouldn't be home until late due to work. After their conversation, Sean is approached by his co-worker, Erika. She smiles tells him that she had a wonderful time last night.
Sean would continue to assist other FBI agents in the search for Ike Dubaku. After the attack on the Boyd Chemical Plant was ceased, Sean was the one who reported the news to Larry Moss. Afterwards, Sean once again had a intimate conversation with Erika. She was wondering when she would get to see him privately again. After leaving, Sean was approached by Janis. She scolded him for making his affair so obvious in the workplace, and that if Larry were to find out, he would be in serious trouble.
Later on, after the threat level was lowered by President Taylor, Sean went to Larry to find out why they haven't been notified about recent developments concerning the terrorists. Larry gave Sean the cold shoulder and this made him very suspicious, believing that Moss knew something he didn't.
Following Chloe O'Brian's arrival at the FBI, Sean was confronted by Janis, who wanted his server key so she could spy on what Chloe was doing from the mainframe room. Janis believed that Chloe was there to replace her. After initially refusing, Sean gave in after Janis threatened to reveal his ongoing affair with Erika to Larry. Janis would later return and inform Sean about Chloe being there to give support to Jack and Renee in the field. Finding this out, Sean would then call Ryan Burnett, a government official working with Dubaku. Revealing himself as the mole, Sean was told about Dubaku having a list of all the people involved in the day's events, a list that included his own name.
After finding out about Jack and Renee following Marika in an attempt to capture Dubaku, Sean put out a warrant on their vehicle. Police officers would barricade Jack and Renee, arresting them. The two would eventually escape and capture Dubaku, along with the storage device containing the list. As it was being transported to FBI, Sean went and found Erika, telling her about all that had just happened. She was also a mole, and the two devised a plan crash the systems in the building just as Chloe began uploading the data drive.
After arriving in the mainframe room, Sean received a call from Ryan Burnett again. Chris informed him that the information had arrived at the FBI, but that he was taking care of it. Erika would soon crash the servers successfully, causing an erase of the files. Chris then kissed Erika passionately before pulling out a gun and shooting her in the stomach. As she fell to the floor and died, Sean shot himself in the arm and placed the gun next to Erika just as Larry came into the room with other agents. Sean said that he found out Erika was the one responsible for issuing the warrant on Jack and Renee, and after following her to the mainframe room, shot her in self defense trying to prevent her system crashing.
Larry then got a call from Chloe, who was able to retrieve the files after their deletion. Being informed of this, Sean was told by Larry to go be checked out by the medical doctor downstairs. Sean would instead go grab his jacket from his desk and begin heading out of the building. However, before he could make it, Sean was spotted by guards and placed into custody. Larry wanted answers, but Sean insisted on speaking to his lawyer. He was then placed in a holding cell.
Rhys Coiro was a series regular for Season 7 only, appearing in the first 10 episodes.