Her books have been translated into over thirty languages, have sold more than eleven million copies worldwide, and have spent combined months on the New York Times Best Seller list.

Her titles include The Betrayal of Natalie Hargrove and Fallen, which reached number 1 on the New York Times Best Seller list for children's chapter books.

Kate has stated that experience of the "Old South" in the Atlanta area (she went to college at Emory) inspired her to set Fallen in a Civil War era academy.

Unforgiven, a spin-off novel featuring the side-character Cam Briel from the series and his love Lilith, was released on November 10, 2015.

Kate's in the process of publishing an interlocking paranormal trilogy of Los Angeles rom-coms, starting with 2024's What's in a Kiss?.

In her twenties, while she was working as a publisher in New York, her overseas boyfriend broke up with her upon her arrival to meet him for a romantic motorcycle ride down the Amalfi Coast.

[20] Kate has said she mysteriously discovered original recordings from the novel Unforgiven by Cam and Lilith's band Revenge.