Ježek also competed at the 2008 Summer Olympics in Beijing. In the C1 event, he finished fourth in the qualification round, thus progressing to the semifinals. In the semifinals he finished second, managing to reach the top eight and the final round. In the final he finished fifth. At the 2012 Summer Olympics in London he repeated his 5th position in the C1 event. He also started in the C2 event with Vavřinec Hradilek where they finished 9th after being eliminated in the semifinals.