Zoë Sedney gained her first international experience in 2017 when she won the gold medal at the European Youth Olympic Festival in Győr in the 200-meter run in 23.74 s and in the 100-meter hurdles in 13.37 s. In addition, she won the silver medal in the Dutch 4 x 100 meter relay in 46.05 s. In the following year she won the silver medal over the youth hurdles at the U18 European Championships there in 13.34 seconds. In 2019 she reached the semi-finals over 200 meters at the U20 European Championships in Borås, Sweden , in which she was eliminated with 23.93 s, but won the silver medal in 44.21 s with the relay.
In 2017 Sedney became the Dutch indoor champion in the 200-meter run.