Year 9 Tupton Hall student Isaac Helps was first across the finish line at the Redbrik Chesterfield Half Marathon fun run.
Isaac, 13, is a member of Chesterfield & District Athletics Club and it was the first time he had done the 1.5 mile race.
He came through in first place with a time of 8 mins 59 seconds. His sister Macy, a Year 6 pupil at Deer Park Primary School in Wingerworth, was the fastest female across the line with 12 mins 43 seconds.
Mum Lisa said: "They both really enjoyed it and Isaac says he can't wait until he can do the full half marathon."
The pair did a short interview with Peak FM which aired the next day.