In 2012, she starred in the film Fat Kid Rules the World and an episode of Jane by Design. In 2013, she appeared in an episode of Vegas and began playing Rebecca Bowman, a rebellious Amish girl on the Cinemax series Banshee. She originally auditioned for the role of Deva Hopewell, but: "They said, 'She's too old or too sexy' or whatever". While in Philadelphia for her grandmother's funeral, the producers asked her to go back to New York to read for Rebecca, after which she won the role. In March that year, she appeared in a pictorial in Maxim magazine.
^Simmons has stated both her birthday (July 23), and her age (18 in June 2011), making her birth date July 23, 1992. Simmons, Lili (20 Nov 2011). "Tweet". @Liliflower33 (confirmed). Twitter. Retrieved March 3, 2014. My birthday is July 23 Simmons, Lili (29 June 2011). "Tweet". @Liliflower33 (confirmed). Twitter. Retrieved March 3, 2014. were both 18