Sam used to date Leah Clearwater, Emily's cousin, but after he phased into a wolf and imprinted on Emily, they became a couple, breaking Leah's heart in the process. Their Life and Death counterparts are Samantha Uley and Elliott Young.
- "You saw what happened to Emily. Sam got angry. Lost it for a split second. He'll never be able to take it back."
Sam Uley was abandoned by his father at a young age. For this reason, he grew up as a very mature person and took matters very seriously. In high school, he dated Leah Clearwater. Sam first phased around the time the Cullens moved back to Forks. When his power awakened, he remained in his wolf form for over one week before he finally became human again. Since he had no guidance at the time, he didn't know what happened to him until the Quileute elders Billy Black, Quil Ateara III and Harry Clearwater explained to him about the Quileute's magic, something he had only thought of as myths and superstition.
Emily Young was second cousins with the Clearwater siblings, living outside on the Makah reservation at the time. She was especially close to Leah. Before Sam phased, she had met him countless times and was very fond of him.
After finishing high school, she began teaching art at the high school on the reservation and local college.
After Sam returned to his human form, he imprinted on Emily when she came to visit her cousins, causing him to break up with Leah. He went to Emily's home to tell her that he was in love with her. Emily wasn't surprised, although she didn't know why at the time, but she ordered him to leave and told Leah what happened.
Emily resolved to get to the bottom of things when she saw him again. As she expected, he returned the next day, and she sat down with him and demanded answers. Sam revealed everything, and transformed in front of her in the woods. Thrilled, she began meeting with Sam regularly and asking questions about the legends of the tribe. Happy to please her, Sam told her whatever she wanted to know and even brought other members of the pack to meet her after they transformed.
Despite her newfound feelings for Sam, she continued to struggle. She felt like she was betraying her cousin, and forced herself to keep pushing Sam away from her and back to Leah. Eventually, rumors spread about her and Sam. Her mother found out from friends, and asked Emily how she could betray her closest friend and cousin. Realizing that things had gone much too far, Emily became ashamed of herself for what they were doing and told Sam to leave again. Knowing he could not disobey, Sam despaired. She then told him to go back to Leah. This was the only thing Sam could refuse her. He loved Leah still, although not the way he loved Emily, and he would not force her into a false relationship. Knowing that Sam's attitude towards Leah was actually more honorable than her own, Emily was angry at herself, and very ashamed. She lashed out at Sam, telling him he was just like his father by refusing to take responsibility for the decisions me made. The insult was far worse than Emily had anticipated, and it had tragic results: She was standing too close to Sam when he lost control and accidentally phased into his wolf form and slashed the right side of her face, creating deep scars that distorted her features, pulling down the corner of her eye for her mouth.
Thinking he had killed her, Sam was hysterical, and he couldn't control himself enough to transform back into his human form. Luckily, Jared was in wolf form and found out what happened, and immediately contacted Paul. He then raced to the scene, and Paul arrived shortly afterwards with Sue Clearwater. When she regained consciousness, Emily was struck by the concern and love Jared showed; even though she barely knew him he looked as devastated as if he held his own sister. Sam hid in the background, too upset and horrified to return to his human form. Emily tried to tell him it wasn't his fault, but her mouth hurt too much to talk and Sue urged her to stay silent to minimize the damage. Sue was able to stabilize Emily, and took her to the hospital.
At the hospital, she explained to the doctors that she was attacked by a bear up North during Salmon Spawning Season in order to protect the tribe's secret and from Sam being accused of abuse. She then asked to see Sam, who begged her to tell him to commit suicide. He wanted to get away from the pain of what he had done. It was only then that Emily truly understood how tightly bound to her Sam was, and she realized that she didn't feel complete without him. She told him not to hurt himself, and that she loved him. When she gathered her courage and told Leah, it destroyed their relationship, which hurt both Emily and Sam although they understood Leah's pain. They finally became a couple, and eventually became engaged.
Sam has never forgiven himself for hurting Emily, and blames himself for Leah's pain and bitterness. He also blamed the Cullens, because their return to Forks caused him to phase into wolf form and forced him to give up a scholarship for college to become Alpha wolf to protect the tribe.
- Main article: New Moon
As other Quileute youngsters begin to phase, Sam takes the responsibility of guiding them and ensuring the protection of their reservation. Emily engages in feeding and taking care of them.
Their relationship takes a serious turn when Leah, Emily's cousin and Sam's ex-girlfriend, unexpectedly joins the pack. Though Leah had found new understanding to the situation and forgave them, she still finds it hard to be around Sam and be constantly reminded of how much she still feels for him, and how he will always know how she feels because of their telepathic link in the pack.
- Main article: Eclipse
Sam, Emily and Leah's triangle story is explained by Jacob when he talks to Bella about imprinting. According to him, Sam has hated himself for hurting Leah so deep, but cannot undo what he'd done.
Sometime after Leah phased, Sam and Emily are forced to deal with her and her relentless pain over losing Sam, even though she has forgiven them and agreed to be Emily's bridesmaid. Because they share a telepathic link to each other, Sam and Leah are constantly reminded of what they went through and she is still going through, and she takes it out on the entire pack by letting them feel her pain.
- Main article: Breaking Dawn
In the midst of Breaking Dawn, Leah tells Jacob that she loves Sam enough to be happy for his happiness with Emily but refuses to see it, because it is unbearable for her to watch and be constantly reminded of how much she still feels for him.
During Christmas Day, Emily and Sam visit Charlie to make a celebration facade with the Cullens and Jacob's pack.