Harrison debuted on the ISU Junior Grand Prix (JGP) series at the start of the 2014–15 season, placing 15th in the Czech Republic and 14th in Estonia. In November 2014, she won the junior gold medal at the British Championships after placing first in the short program and third in the free skate. She also finished first at the Bavarian Open in February 2015, competing in Junior Ladies group I. Having attained the minimum technical scores, she was sent to the World Junior Championships in Tallinn, Estonia in March 2015. Her short program result, 27th, was insufficient to advance to the free skate.