Quinn was born in Texarkana, Texas. She began taking weekly acting lessons from retired director and producer Martin Beck after performing in her community"s performance of The Nutcracker at age six. In the sixth grade, she auditioned at the Young Actors Studio where she performed for the program"s director, Linda Seto, and representatives from the Osbrink Talent Agency.
After six months of "intensive training", Quinn signed a contract with the Osbrink agency.
Subsequently, she signed with Management 360. Since 2009 she has starred in the American Broadcasting Company drama/mystery series Castle as Alexis Castle, the main character"s daughter.
She also voiced Princess Bloom in the Nickelodeon adaption of Winx Club. In March 2014, Quinn appeared as the voice of the sentient computer "Faculty", in the episode "Numbers" of the podcast series Welcome to Night Vale.