Rosemary was raised in a mansion by her wealthy parents. She was also raised aware of her family's lineage—that she was from a long, secret line of Herondales that the Clave was not aware of, and was taught the cruelty of the Clave and their Laws,and that she was also part-fey, belonging to a line the Unseelie Court wanted dead because of their lineage. Due to the constant threat, she led a sheltered life, constantly moving around, much to her annoyance. She was also trained in combat from a very young age.
When she was sixteen, Rosemary met a thief who called himself Jack Crow in Los Angeles, who had the Sight. The pair began spending more time together, mingling among the Downworld, with Jack conducting business at the local Shadow Market. They eventually fell in love.
After a while, her parents informed her of their intention to once again relocate. Rosemary was frustrated and ran away for the day. She never truly understood the danger they were in, confident in their years of survival, until she came home that night to find her parents murdered.
Rosemary sought out Jack and intended it as their last goodbye. Rosemary told him about her secrets and Jack insisted on joining her on the run instead.
The couple moved constantly, to various places including Berlin, Tokyo, Rio, and Reykjavik, and established new identities—with new names and new faces—and connections to the Downworld every time, both for Jack's business and for their safety. Jack did what he could to protect her and used himself as a pawn, pretending to be the lost Herondale to pin himself as a target instead of her.
While in Paris, she and Jack were tracked down by the Silent Brother Zachariah who hoped to protect the lost Herondale. The couple had anticipated him and made it look as if Jack was the lost Herondale and not her.
Meanwhile, as agreed upon, Rosemary and Jack parted ways, planning to meet again at their "old place" in the Los Angeles Shadow Market once the trail on them has gone cold. Rosemary reaffirmed to him that it was their safest option, as she did not want him around for the unsafe circumstance she was about to enter.
When Johnny left, Rosemary was attacked by an Achaieral demon then helped by the Shadowhunter Céline Montclaire. Rosemary asked for an iratze and warned Céline about trusting Valentine Morgenstern, suspecting that she would make a perfect candidate for Valentine's devious ways of recruiting followers, before sending her away to speak to Brother Zachariah.
The ruse failed as the Brother saw through their plan and recognized the traits of a Herondale in her. When Rosemary refused to join him for protection, Zachariah returned her Herondale heirloom, informing her that he'd charmed it so she could call for him if she ever needed help.
|“||Once she has Christopher, she finally understands her parents, their lives consumed by fear. Not for themselves, but for her. She refuses to impose that on her son. She wants a better life for him, something more than barbed wire and security alarms. She wants him to have a home. She wants him to know trust, to know love. She wants to save him from hiding.||”|
–Rosemary's realization about her life, Through Blood, Through Fire
Rosemary and Jack eventually had a son together. With her son Christopher's life now also in danger, Rosemary became less than willing to live on the run, not wanting to raise Christopher in those circumstances. Rosemary decided to distance herself from them, not wanting the faeries to know that she had a progeny and another Heir to hunt, and made Jack agree to not tell their son the truth about his lineage so that he might "grow up unafraid of the world."
At first, Rosemary simply lived apart from her husband and son and watched Kit from afar. Eventually, however, when Christopher was three, Rosemary was found by the fey. She decided to lose all contact with them, forcing Jack to take on new identities that she wouldn't be able to seek out to protect them.
Because Jem Carstairs and Tessa Gray knew her identity and the danger she was in, they were keen to find her and her family in an effort to protect the lost Herondales. Eventually, in 2012, Rosemary, overcome with loneliness and missing her husband and child, returned to Los Angeles, if only to feel closer to them again because she did not truly approach them. She lived in a bungalow where she imagined a home for them, building up a garden she thought her son might live.
She was ultimately tracked down by the Riders of Mannan. Realizing that she was in grave danger, she used her charmed heron necklace to contact Jem, asking him to protect her son. The Riders tortured her to find out if she had a child, though Rosemary stood her ground and did not give up any information about Kit. She had already been killed by Fal in her home by the time they arrived.
While on the battlefield in Idris, the Riders themselves taunted her son Kit with the fact that they'd tortured and killed her. Kit's powers were triggered for the first time by the shock and anger at the news.
Rosemary had blond hair and blue eyes.
- The Wicked Ones (first appearance)
- The Lost Book of the White (alluded to)
- The Land I Lost (mentioned only)
- Through Blood, Through Fire
- Lord of Shadows (first mention)
- Queen of Air and Darkness (mentioned only)
- The Lost World (mentioned only)
- Forever Fallen (mentioned only)
- The Wicked Powers (will be mentioned)
- When Kit was growing up, Johnny told him that his mother was a Vegas showgirl who left them after she gave birth to him.