His first major victory came at the 2008 IAAF World Indoor Championships, where he won the 3000 m gold medal. He was the 2006 World Junior Champion over the distance and also won a cross country junior bronze medal that year. He took a continental silver medal at the 2007 All-Africa Games. Tariku has finished in the top eight of 5000 m finals at the 2008 Summer Olympics and at the World Championships in Athletics in 2005 and 2007.