Sam is a nurse and single mother; she has a son, Alex. Alex was born when she was fifteen; she has had to raise him mostly on her own.Viewers first meet Sam in the Season 10 where she distinguishes herself by quickly and effectively giving an intravenous sedative to an unruly patient. Sam shows herself to be an assertive, experienced, and talented nurse throughout the episode, though she loses her professionalism a bit when she discovers Dr. Luka Kovac's unknowing part in her son Alex's diabetic fit while he befriends the boy. She replaces Abby Lockhart who was head nurse, but decided to become a doctor instead.
Sam soon notices a bond between Alex and Luka. Though initially uncomfortable with Luka's involvement with Alex, Sam eventually accepts it and becomes good friends with Luka. Later, a romantic relationship develops. Unexpectedly, Alex's father, Steve, returns and attempts to push Luka out of their life. When she discovers Steve might stay permanently, Sam panics, packs up, and runs away. Before doing so, however, Luka runs to her, trying to get information from her as to why was she is doing this. Ignoring him and his slams on the car, fighting tears, she drives away. Sam has had a history of picking up and moving around the country to escape Steve. She worries that he will ruin her and Alex's life and that they cannot coexist with Steve. She does come back thanks to Luka who finds her at a motel and brings her back. They move in together.
Throughout season 11, Sam and Luka lived together, and Luka was a surrogate father for Alex, even going and meeting with a school official. At the end of season 11, Alex runs away to find Steve, hitchhiking, after a confrontation with Sam. He is out to find Steve in Colorado, even though Sam has omitted the fact Steve is in jail on robbery charges. Luka and Sam are frantically searching for him in the opener of season 12. Sam is desperately worried about Alex because of his diabetes, and his lack of insulin could have resulted in a coma or even death. Sam immediately gets in the car and drives non-stop to Colorado. Luka worries about Sam because they have been driving non-stop, and even hit a deer which completely destroys the windshield. Sam and Luka finally find Alex, he's okay and said that he knew how to take care of himself. But, he still looked exhausted. After a tense conversation about Sam and Luka's relationship and their future together, they get to agree to disagree that Luka wants more kids and that Sam doesn't.They break up soon afterward.
Alex's father is then taken to a jail in Illinois. In the Christmas episode, she lets Alex visit his father in jail. Later in season 12, a very wealthy patient named Richard Elliot,enters the ER. He suffers from a debilitating disease for which he needs an in-home nurse. He takes a liking to Sam, and offers her the position of head nurse. He reassured her that she would still be able to keep her job in the ER while being his in-home nurse. Since the offer was being an in-home nurse, he invited her to live in a section of his mansion for convenience. She declined at first, but later on, she finds out that Alex cannot be in the tutoring program because of the lack of funds. She arrives at the man's house, and asked if the offer still stands.She has now moved into the mansion with Alex and they are living a good life. Sam even took a chauffeured ride to work, causing her co-workers to speculate. Luka even inquires about how she is, probably curious to learn more.
Steve, a medical assistant named Mary and another prisoner named Rafe hatch an escape plot: Steve and Rafe injuring themselves and then escaping from the hospital. They stab Luka with a syringe, as Sam looks on in horror. She does her best to try to patch him up, but the criminals drag her out. They proceed to start shooting up the ER once police catch on, using Sam as a hostage. Abby Lockhart and Jerry Markovic are hurt in the shooting, possibly fatally. Steve drags Sam outside, towards the getaway van. She begs him, to think about Alex but as it turns out, he already had, and Alex is tied up inside the van. Sam immediately gets in the van after seeing Alex, and later, Steve tells her that God spoke to him, and told him he had to get his family back together.
With Sam and Alex as hostages, the three try to escape to Canada.; Sam attempts to get help, and a police officer chases after the group, ending with the officer's (presumed) death. As the three argue about the escape plan, Steve shoots both Rafe and Mary, leaving only Steve, Sam and Alex. Steve tells Sam that he would rather have himself, Sam and Alex dead than apart, and then proceeds to rape Sam. Some time after, Sam, lying next to a sleeping Steve, proceeds to make her getaway with Alex. As she is about to escape, however, she returns to the still sleeping Steve, grabs his gun and kills him.The next morning, she and Alex drive back to Chicago. Tired and panicked from her ordeal, she contacts Richard Elliot, who gets her an attorney, and instructs Sam to tell everyone she was raped by Steve and later killed him in self-defense. Despite an assistant District Attorney's suspicions that Sam is lying, Elliot, through his close friendship with highly-placed city officials, manages to get Steve's death listed as a justifiable homicide, thus ending Sam's legal troubles, although the ordeal's emotional toll on Alex is currently unknown. Alex results in telling his friend that his dad will die, relating to the trauma of his own dad's death. He also steals a credit card from Archie Morris, and (accidentally) sets their house on fire by playing with alcohol. Sam ends up sending her son away to a Private School for troubled children.
Sam gets a new haircut and begins a new life without the stresses of a single mother. She has a couple of romantic interests but decides she's not looking for anything serious.