Actual person portrayed: Olivia Wilde (House MD)
Samantha was a bit of an unexpected surprise; her mother and father had been married eight years and had worried that they would be able to have a child of their own. Samantha's mother adored her stepson John, though, and both parents had been happy with only having him in their lives. But all three members of the Hagen family eagerly awaited the new arrival.
John was ten years old when she was born and had always considered himself her protector; he had no problem taking care of her and he didn't dislike that his parents had less time with him than before. In fact, when his stepmother had asked if he had any name ideas for her, he ended up choosing her entire name: Samantha Angela Hagen (later Samantha found out she was named after the only two girls he could stand at the time, but it didn't matter to her because it was the thought that counted).
One of the things that made her childhood hard was that she looked much more like her mother than she did her father, and neighborhood children would often make fun of her by saying she wasn't really related to her brother. Since the two of them were extremely close she took great offense to that, and it caused her to get into a few fights. When her brother taught her how to win fights, she got the upper hand and eventually the fights stopped because no one wanted to go up against her after that.
She was incredibly smart and her parents encouraged this; she ended up graduating from the University of Miami at nineteen years old and emerged with a dual major Bachelor's degree in biochemistry and sociology. Later she earned a Master's degree in psychology. She's currently working on another Master's in sociology.
Her parents were killed when she was sixteen in a car crash and instead of becoming an emancipated minor she went along with her parents wishes and went under the guardianship of her brother. He moved out of his apartment and into their childhood home, hoping not to disrupt her life too much. She appreciated it very much, but she realized that there was a change in her brother and it worried her.
She entered the MDPD academy out of college and passed all her tests. She spent two years working as a beat cop for the MDPD before she was admitted to the FBI's training program. That caused a huge blow out between her and her brother, which culminated in them not speaking to each other for almost a year, until he finally accepted that she wanted to be more than just a cop.
Her first job with the FBI was as a regular field agent. She worked closely with the FBI labs and was eventually allowed to help process evidence from the scenes she went to. That gave her team a crucial inside line as to what the evidence could prove for their case. She also began working on her Master's degree, hoping that the extra degree might impress the Behavioral Analysis Unit.
It did, eventually. She became an member of the BAU at the age of twenty-four (the same year she got her Master's degree) and stayed with them until she was twenty-eight. And then something happened that completely shook her: her brother comitted suicide in the MDPD ballistics lab. She was devasted and took some time away from the FBI, going so far as to move back to Florida and into her childhood home (which both she and her brother had decided to keep instead of sell) while she went through her brother's things. Eventually she went back but it wasn't the same, and she left the FBI when she was twenty-nine.
She took a few months to re-evaluate what she wanted and where she wanted to go and eventually decided she wanted to work for a police department again. She looked around at police departments and applied for the NYPD. When she heard back about a job it was suggested that with her background she see about becoming a CSI instead of just a detective. She followed up on that and met with Mac to see about what it would take to join. It took a little while, but eventually she entered the NYPD as a CSI and detective third grade.
She had left her life in Miami behind (except for the house, which she refused to sell) as well as her life in Quantico and decided to start over completely. At first she didn't open up to her new co-workers about anything regarding her past, but slowly Hawkes and Stella began to pry things out of her and she opened up a bit. Flack was another person she opened up to, and the three of them became her closest friends in the NYPD. She still didn't tell anyone the main reason she left the FBI though, glossing it over as a "really bad thing" that had happened in her personal life.
Eventually, she began to fit in, and then she got assigned to a cross jurisdictional case with Miami and her life changed yet again, only this time for the better as she made her peace with what had happened there. When she came back to New York, she was ready for whatever awaited her there.
She does have some family left; however, she isn't extremely close to them. Her uncle William Hagen, Sr. and his wife live in Louisiana, as do her cousins William Hagen, Jr. and Angelicalee Dareau (who go by Drew and Angel, respectively). They are only a little older than her and family visits could get very interesting. Drew was there for her for a little while after her brother died and that's smoothed out the competative streak between them a bit.