Born in
Prague, Vadlejch took part in international javelin competitions from a young age, reaching the finals at the
2007 World Youth Championships in Athletics,
2008 World Junior Championships in Athletics and the
2009 European Athletics Junior Championships. His senior debut followed at the
2010 European Athletics Championships, where he threw in qualifying only. He competed in the
javelin throw at the
2012 Summer Olympics and placed 25th with a mark of 77.61 metres. He was eliminated in the qualifying round at the
2011 World Championships in Athletics,
2014 European Athletics Championships, and
2015 World Championships in Athletics. Vadlejch had his breakthrough season in 2016. He reached the final at the
2016 Summer Olympics, taking eighth place, and took victory on the
2016 IAAF Diamond League circuit, with three wins and a personal best of in the process. At the
2017 World Championships he set his new personal best, , winning the silver medal.
2020 Tokyo Olympic He won the silver medal in the Men's Javelin throw event. He finished at the second spot behind India's
Neeraj Chopra.
2024 In November 2024 he was declared for the forth consecutive time, Czech Athlete of the year. He came in first just before bronze javelin thrower medalist in
Paris 2024,
Nikola Ogrodníková. ==International competitions==