Yomif Kejelcha made his international debut at the 2013 World Youth Championships in Donetsk, winning gold in the boys' 3000 metres with a time of 7:53.56. At the Ostrava Golden Spike elite meeting in May 2014 he placed second over 3000 metres in 7:36.28, losing only to Kenya's Caleb Ndiku; he defeated 2008 Olympic medallist Nick Willis and former World Champion Bernard Lagat. Yomif won the 5000 metres at the 2014 World Junior Championships in Eugene, Oregon, running 13:25.19; he also won gold, in the 3000 metres, at the Youth Olympic Games in Nanjing later that summer. He finished 2014 as the world youth leader at both 3000 and 5000 metres, and world junior leader at 3000 metres.