While working in the FBI's accounting office, Harrison spent years piecing together and memorizing details, from Fox Mulder's and Dana Scully's expense reports, of their adventures while they were investigating the X-files. (TXF:"Alone")
As a young, eager agent, Harrison herself was later transferred to the X-Files unit from the accounting office. She had a huge crush on Agent Mulder and frequently recalled X-files cases which he and Scully had seemingly solved using some of the strangest of methods. (TXF: "Scary Monsters")
Leyla Harrison was created and named in memory of a fan of The X-Files who had the same name as the character, wrote internet fan-fiction based on the series, and died of cancer on 10 February 2001. The character's attention to the minutiae of and inconsistencies in the history of the X-files is similar to the way fans of the series often exhaustively discussed, on the internet, each episode of The X-Files; as such, the creation of her character can be seen as a way for the show's producers to pay homage to, but also satirize, such fans.
In a casting breakdown used by the production personnel of The X-Files to cast the role of Leyla Harrison, the character was described as follows: "Female, late 20s to early 30s, open ethnicity. A cute, newly appointed agent to an X-files case to partner with Agent Doggett. She began as an accountant for the Bureau, and always had the dream of becoming an agent assigned to the X-files. She is eager and enthusiastic about the position, but her inexperience and ineptitude are frustrating to Doggett although, always the gentleman, he treats her like a gentleman should."
|Agents assigned to the X-Files|
|Arthur Dales||Fox Mulder||Dana Scully||Jeffrey Spender|
|Diana Fowley||John Doggett||Leyla Harrison||Monica Reyes|