After initially moving to New York to pursue theater, she received her breakthrough role as Anna in the ABC series Once Upon a Time. She then booked starring roles in Freeform's Dead of Summer and Lifetime's You.
Her only previous acting experience was in a couple of student film productions.
She studied acting at the University of North Carolina School of the Arts.
She was born to parents Dean Franklin Lail and Kay Lurene Surratt in Williamson County, Texas, later moving to Asheboro, Randolph County, North Carolina. She has a sister named Kathryn Dean Lail. In April 2021, Lail married dentist Nieku Manshadi.
She co-starred in You alongside Penn Badgley.