|“||Sam, is it really you? (puts hand on Sam's chest) And you're so firm!||”|
Her online name was samlicker81, and she was the webmistress of morethanbrothers.net. Carver Edlund aka Chuck Shurley contacted her and enlisted her to get a message to Sam and Dean Winchester. At first, she believed it was a prank before he told her that everything in the books was real which delighted her as she thought it was. Becky then went off to meet the Winchesters, after finding them she was greatly excited. It was obvious from her reaction upon meeting the boys that she was a Sam Girl, due to being more interested in him than Dean. She then gave them Chuck's message though it was rather complex for them to understand.
She later used Chuck's phone and tricked the boys into going to the "first ever" Supernatural convention. When Sam managed to recall her name, she blurted out that she couldn't stop thinking about him, either. While there, she continued to flirt with Sam (who wasn't flirting back) so she was initially oblivious to Chuck's crush on her. Only when Chuck saved the hotel manager did she notice him and want to be with him. So, she proceeded to 'break up' with Sam gently, believing that she had hurt him. He played along, which made her happy. It was Becky who revealed to Sam where the Colt was, because she'd read the book. She told Sam that Bela gave The Colt to a demon named Crowley.
Sometime later she and Chuck broke up, with Becky thinking she may have intimidated him with her sexual drive.
She appeared again in Season Seven, Time for a Wedding! when she used a potion to drug Sam. While drugged Sam married her, making her wild dream come true. With Sam as her husband, she quickly headed over to RSVP to her high school reunion to show off. On the way out she bumped into Guy, who gave her more potion. She and Sam went back to their place and began working on a case together. When the potion started to wear off, she knocked Sam out and tied him up until she could get more from Guy. She was horrified to learn that he was a crossroad demon and not a wiccan as she thought. Guy offered her a 25-year deal, but Sam convinced her not to take it and to help them defeat Guy. She teamed up with the Winchesters and Garth to stop Guy by pretending to take the deal, and then tricked him into a devil's trap.
Becky was excited that the ruse worked at first, but upon getting a look from Sam and Dean, slinked off to watch from a safe distance. Guy revealed he had a demon "intern" named Jackson committing murders to call in his deals early. Jackson appeared, attacking Dean and Sam who told Becky to run when the fighting started, which she did only long enough to grab the demon-killing knife and stab Jackson in the back, killing him to her amazement. Her quick action saved Sam and allowed Dean to overpower Guy after Sam tossed him the knife. As the Winchesters tried to force Guy to break his deals, Crowley appeared. Becky excitedly recognized him, to his bemusement. Crowley, extremely annoyed by Guy's deal-making antics, decided to make an example of him, and to nullify all 15 of his recent deals. Sam later obtained an annulment from Becky, but as she saved his life, grudgingly told her that she was a good person, and encouraged her to find someone who loves her for her. She and Garth then made eye-contact that lingered, which Dean noticed and immediately shut down.
In Slumber Party, Charlie referred to a person on the internet publishing the Supernatural books on-line. The said person had the username 'BeckyWinchester176' that most likely referred to Becky Rosen. Sam quickly denied any knowledge of who it was but was clearly uncomfortable.
In Various & Sundry Villains, Sam realizes that Dean might be under a love spell and reminds him of the incident with Becky in Las Vegas as an example. Unfortunately, Dean did not remember the incident, nor Becky, anymore.