Sean was born in August 8, 1969 to a lower middle class family from Hyde Park, Los Angeles, California. His father worked as a construction worker and his mother was an elementary school teacher. He is the eldest of four children.

He had always dreamed of being a police officer. As a child, his favorite toy was his police kit. He would walk around the house 'arresting' people for everything. Every time he saw a police car in the street, he would smile, wishing that he was the one driving it.

Sean's dream finally became true when he joined the LAPD in 1991, after earning a bachelor's degree in Criminal Justice Studies in California State University, Long Beach. Working for twelve years in the Southwest Community Police Station as a patrol officer, he got to become well liked and respected in the community.

In 2000 he met a girl named Camilla Lopez. They had a short but intense romance that lasted a little over two months. A couple of years later he met her again and found out that he had a daughter. He found it out only a few days before Camilla and Gabriella, their child, moved out of LA.

In early 2003, after doing some amateur detective work, he was able to locate his daughter. He tracked them down to Sierra Falls, but he decided to post pone their meeting. It would take two years before he
finally built the courage to meet his daughter. They have slowly grown closer, and with Sean's move to Sierra Falls, things are getting better with Camilla as well.

In 2003 after four attempts, Sean passed the LAPD SWAT exams. He excelled at the training, and graduated at the top of his class. He was then assigned to a Scout position in one of the SWAT teams. During his time on SWAT he worked in several high profile situations, all of which were successfully controlled.

In mid 2005 his team was called to serve a high risk warrant on a suspect of five murders. The suspect was believed to be armed and with at least one hostage, a 17-year old girl who he had abducted three days before. The suspect was alerted of SWAT's presence by an intricate alarm system that he had set up in the house and used the girl as a human shield. The team managed to apprehend the suspect when Sean, in a calculated risk maneuver, moved quickly towards the suspect, who turned to shoot at him, while Sean' teammates moved swiftly and disarmed the man, taking him into custody. The element received the Police Comission Unit Citation for its actions.

In early 2007 Sean's element was deployed to an old apartment building where a group of cultists had been living for some years. The police received an anonymous tip of a mass suicide plan which involved of a very large amount of explosives being detonated in the building, risking the entire neighborhood. His team was sent in to clear the building and secure the explosives. When the team reached the basement they found the decaying corpses of eleven children, presumably the cultists' own daughters and sons. That was a deep trauma for all of the team. The event forced the early retirement of two officers. After the incident, he decided that it was time for a change, so he applied for a lateral transfer to Sierra Falls, looking for a fresh start in a smaller department.

Even after 17 years in the force and in spite of everything he witnessed, he still believes deeply in his duty, to protect and to serve, and this is strongly reflected in his personality. He is usually described by his friends as 'the loving giant'. He can intimidate most people rather easily with his body, but he is actually a very gentle and protective person. These traits become even more perceptible when he is around his daughter. Despite not being around during her childhood, he has grown attached to her.

He is a solid tactician and a very good leader that likes to lead by example. He is a bit of a workaholic and is always very professional, even when he's not supposed to. Some of his friends say that he has his own State Department, because of his diplomat-like personality.

Sean is in top physical condition, his build is rather intimidating really. Even tough he has left SWAT, he still maintains the same physical training standards that he was required to maintain in the unit. He tries to maintain a low profile when it comes to clothing, but his large frame always makes him stand out.

He carries his Kimber 1911 as backup while on duty.