She competed at Miss Belgium on 9 January 2011 in Knokke-Heist. De Jonckheere, who stands 1.73 m (5 ft 8 in) tall, competed as the representative of West Flanders against 15 other models. She won the contest, gaining the right to represent Belgium in Miss Universe 2011 and Miss World 2011.[3]
At the Miss Universe 2011 pageant, De Jonckheere represented her country. In the contest, which was broadcast live from São Paulo, Brazil on 12 September 2011, she and 88 other models participated, but De Jonckheere failed to reach the Top 16.[4]