Gardiner worked as a co-executive producer on
Killing Eve. She was hired by
Emerald Fennell during the show's second season to be a “writer’s friend” and act as a conduit between the writers and actors. She worked in the show's writers room. Gardiner worked as an executive producer on the television adaptation of
His Dark Materials. Gardiner wrote the final two episodes of the series. Gardiner joined the project alongside
Mark Mylod, who would also serve as executive producer and direct several episodes of the show. The pair had previously worked on
Succession together. Gardiner's sister, Josephine, later joined the writers room for the show. ==Personal life==