Kelly is a former Great Britain and England sprinter, specialising in 400m events. She transitioned to the 400 meters at the age of 20 and first represented Great Britain at the 2007 World University Games. The Sale Harrier athlete and former British Champion has won medals for England and Great Britain at 9 major championships with the highlight being winning a Bronze medal as part of the 4 x 400m relay team at the 2016 Olympic Games.
After finishing university in 2009 Kelly, originally from Staffordshire, moved to Manchester to enhance her training. She became a PE teacher but decided to leave her role at Denton Community College to become a full time athlete and dedicate more time to training in 2015.
As an athlete the one thing that Kelly would go back and tell herself would be to get a mentor. As a result of this she has set up Elite Margins, a coaching and mentoring company which delivers talks, workshops and 1-2-1 mentoring to athletes and pupils, for those taking part in all sports, at all levels and of all ages to help support them in unlocking their personal best.