Lightfoot was born in Coventry. She took up the sport after first learning to ski at the age of nineteen. She is a Sergeant clerk in the Adjutant General's Corps. She was selected as part of the Team GB squad for the 2014 Winter Olympics in Sochi. Her trainer is Walter Pichler. Lightfoot achieved a new personal best at the 2017 Biathlon World Championships in Hochfilzen when she finished 32nd in the individual race.