Lyndsy Fonseca was born in Oakland, California, raised first in Alameda and then Moraga, California. Lyndsy competed in the International Modeling & Talent Association, where she was recognized as the second runner-up for "Young Miss Dancer of the Year" and was the first runner-up for "Miss Barbizon Young Miss Talent of the Year". There, she was discovered by a manager and agent, and then she immediately moved to Los Angeles for her first pilot season at the age of 13.
Fonseca has recently had success on the big screen, her film credits include: The Ward (2010), Hot Tub Time Machine (2010), Fort McCoy (2011), and Kick-Ass (2010).