Leslye was born and raised in Queens, where she was enrolled in swim lessons at the Flushing YMCA at the age of four. Her love for the water was instantaneous -- as Leslye soon advanced to the Y's swim team, the Flushing Flyers, when she was just six years old. She was soon competing in New York state championships. She later swam for Bayside High School, where her studies focused on engineering, and she raced in the city high school championships in her best event, the 400 individual medley. Leslye worked as a lifeguard during and after high school and is currently studying nursing at Queens Community College.