Rose makes first appearance in the "Pilot" as a woman that is obsessed with Charlie. She and Charlie develop a close friendship, and she starts to regularly hang out with Jake but is still in love with Charlie. She often gave him relationship advice, even though she subtly acknowledged her remaining feelings for him.
In late season 4 she moves to England at which time Charlie discovers his love for her but returns in mid season 5 and "takes care" of Charlie for two weeks. Rose came back in Season 8 and told Charlie she was getting married, but it was a fake wedding, and all the people attending were mannequins. She claims to now be married to "Manfred Quinn, a model and important figure in the men's fashion industry. This prompts Charlie to confess his feelings for Rose even asking her to elope with him but she refuses. Rose and Charlie have an "affair" which involves quick trysts and Charlie even taking Rose on a romantic getaway weekend to Paris. Also in season 8, Rose quickly deduces that Alan is involved in a Ponzi scheme which results in him getting large sums of money from Charlie, Herb, Judith, Evelyn and Berta. Alan goes to her house to blackmail Rose, claiming that he'll tell her "husband" about her affair with Charlie, only to discover the truth about "Manny Quinn". Thus resulting in Rose and him come to an agreement. Rose gives Alan the money he needs to pay back his family the money he took from them, without them discovering the truth about the Ponzi scheme and Alan keeps the Rose's secret about ``Manny Quinn`` from Charlie.
Charlie and Rose went to Paris, where Charlie proposed to her. Not to long after, Rose caught Charlie in the shower with another woman. The next day, Charlie "slipped" and fell in front of a train, killing him. At Charlie's funeral, it is obvious to see that Alan, Evelyn and Berta think Rose killed his brother. This is furthered by Berta's comment of, "Never cross a crazy woman".
Throughout season 9, Rose was absent and rarely mentioned (only in passing) other than the premiere and during the season. It had not yet even been stated that she still lives next door to the beach house, though one would think that Alan would mention it. This could be explained however, by Rose's possible plotting after losing her only "hobby".
However, in "What A Lovely Landing Strip" she makes her long-awaited reappearance. She sneaks up on Bridget (whom Walden had finally gotten over and is now watching him from the back-door window) and decides to take her on as a pupil in stalking the person of her affections seeing as she is unstable over being rejected by her husband for another woman. In the end of the episode, it becomes clear that the never-ending cycle of love-hate in the beach house is far from finished.
In "That's Not What They Call It In Amsterdam", Rose finally meets Walden, formally, and they hit off. It's apparent that she still stalks the Harper clan, and as a victim of circumstance Walden is stalked as well. She telling him 'everything' that happened with Charlie (not mentioning his murder however). When Walden tells Alan, he starts freaking out. So it is clear the friendship between Alan and Rose is very well over. In the continuing episode, "Ferrets, Attack!", Walden asks Rose to move in. But Rose tells him that she'll think about it (surprise, surprise). Walden gets a coffee invite from Zoey, who wants to get back together. When Walden comes home to tell Alan, he say's 'Isn't that crazy?'. When Alan says 'no', he takes Walden into the living room where Rose and her boxes from home stand and tells Walden, 'That's crazy'. It is clear to Walden he must call it off with Rose. Later that evening, Walden and Rose are lying on the deck, Walden tells Rose he's breaking up with her. When Rose leaves the deck, she calls her pet ferrets to attack Walden. Later, Rose shows up on Zoey's door, 'pregnant' with Walden's baby. Zoey freaks out and calls it off with Walden.
In "Mr. Walden, He Die. I Clean Room.", she picks up Walden, who's on the run from Larry's hitman. Rose takes Walden to a hotel where she says he'll be safe. The two end up having a romantic moment where they kiss. At the end, when Larry calls off the hitman, it's revealed to be Rose who used this experience as an attempt to get close to Walden.
Rose is magnificently educated, having earned her Undergraduate Degree in two years from Princeton University and she also has a Masters Degree in Behavioral Psychology from Stanford University—she falls under the category of the mentally-ill who got into psychology so they could self-medicate.
Rose appears to use her educated skills in "I Always Wanted A Shaved Monkey" to help Charlie and Alan when they have a brotherly dispute.
- Rose has five pet ferrets, all of whom are comically named Charlie.
- She also made the CharlieHarperSucks.com (and waited for Charlie to say something to her and then deleted it) website in the episode "Last Chance to See Those Tattoos".
- Though Alan, Berta and Evelyn (and possibly Jake, Judith and Herb) suspect that Rose killed Charlie, no one has acted on their suspicions by calling the police to investigate Charlie's accidental death.
- According to Charlie, Rose once trained a seagull to swoop down at his face and glued her high school graduation photo to his freshly-shaved buttocks.
- Rose has a full tattoo of Charlie's face on her buttocks.
- Rose has appeared in two episodes in Season 9 in total and three episodes in Season 10. She appeared during the flashback montage in "Oh Look! Al-Qaeda!". She returned in "That's Not What They Call It In Amsterdam" when Walden starts dating her despite Alan's warnings against it because she was stalking his brother Charlie. She has yet to make another appearance
- She stated that she has lost her virginity to Steven Tyler from Aerosmith in "Who's Vod Kanockers"
- Her parents are actually first cousins, meaning Rose's father married his first cousin.