"My husband's gonna have a field day with you."
Jillian was a housewife who was happily married to a powerful attorney named Owen, with whom they had two children. However, she became disillusioned with her lifestyle and somehow joined up with the Libertad Cartel. How she joined up with the organization is unknown, but JJ theorized that she may have become addicted to painkillers and found the cartel while trying to access more. Jillian eventually became the Cartel's second-in-command and supervised its on-the-ground component, urging members to recruit new people into the organization.
In the episode, Jillian meets up with a woman claiming to be a new member of the Cartel, named Sarah Miles. She introduces herself as her usual alias, "Ben Franklin", and tells her to be a better salesperson. Sarah then leaves, and Jillian gets a phone call from her boss, "George Washington", who informs her that Sarah is an undercover agent for the DEA. She then assures George that she knows what to do, and sets Sarah up to be abducted by Jacob DuFour, although she doesn't know about Jacob's true nature as a serial killer. A few days later, while taking her son and daughter to school, Rossi and JJ arrive and take her into custody. While she is initially resistant to their questions, she eventually caves when they threaten to inform her husband about her activities. While she doesn't know about the true identity of George or Jacob's activities, she gives them Jacob's address. She is most likely incarcerated afterwards.