Ashlee Knapp was born in Rahway, New Jersey. She began her dance training at the age of eight at the Omaha Theater Company Ballet with Robin Welsh. At the age of 12, she began studying with Bojan and Stephanie Spasoff at the Rock School of Pennsylvania Ballet. Ms. Knapp entered the School of American Ballet (SAB), the official school of New York City Ballet, full time in the fall of 1999, and in November 2001 she became an apprentice with New York City Ballet. Ms. Knapp joined the Company as a member of the corps de ballet in October 2002.

Ms. Knapp is a 2001-2002 recipient of the Princess Grace Dance Fellowship and a 2001 recipient of the Mae L. Wien Award.