She finished seventh in the long race at the 2004 World Cross Country Championships, while the Kenyan team, of which Jepkorir was a part, won the silver medal in the team competition. She won the Parelloop 10K in race in the Netherlands in 2005. She finished fourteenth at the 2006 World Road Running Championships, helping the Kenyan team win the team competition. She won the 2007 Cross Internacional de la Constitución.