Stephen Cheruiyot Cherono was born and raised in Kenya, showing athletic ability from a young age. He initially made his mark on the international stage with a win at the 1999 World Youth Championships in Athletics over the 2000 metre steeplechase. After the death of his coach and manager Kim McDonald in 2001, he started training under Italian coach Renato Canova, who was already the coach of his elder brother Christopher Kosgei. Christopher was the 3000 metre SC World Champion in 1999. The first success of this collaboration was breaking the World Junior Record in Brussels in 2001. As of May, 2017 his time of 7:58.66 was still the WJR. He then went on to win the 3000 metre SC in both the 2003 and 2005.