He won the javelin title at the All-Africa Games in 2011 and at the African Championships in Athletics in 2012 and 2014; at the 2013 World Championships he placed fourth, losing a medal in the final round. In 2014, he became the first Kenyan to win a Commonwealth Games gold medal in a field event. At the 2015 World Championships he won the gold medal with a throw of 92.72m, becoming the first Kenyan to win a World Championships gold medal in a field event. He won silver at the 2016 Summer Olympics in Rio de Janeiro.