Born in Findlay, OH, Miller grew up in rural Ohio the oldest of three girls. Miller knew from the age of five that she wanted to be an actress. At the age of nine, Miller took her first acting class. Miller graduated from Marysville High School in 1990. After graduation, Miller attended Ohio University to major in journalism. However, she switched gears and decided to major in film and television production instead. While still attending Ohio University, Miller studied acting at University of California, Los Angeles and University of Southern California during the summers. When she graduated from Ohio University, Miller made the permanent move to California in January 1995.
Miller's first guest spot on television was on Roseanne in 1996. From there, she has also appeared in Just Shoot Me!, Charmed, and CSI: Crime Scene Investigation, just to name a few. Miller's film debut occurred in 2001 when she appeared as Skyler in Scared.
In 2002, Miller founded a school called Lights, Camera, Acting!, an acting school just outside of Los Angeles. Miller continues to teach there, despite her busy schedule at GH. When she is not working, J. Robin can be found inventing new allergy-free recipes, watching sports with friends or hiking on local mountains with her dog.