If we equate "will" to "perserverance" then we may have struck upon one of the major ingredients of success. Yet, as the posts above have pointed out, there are many factors that can make success more or less likely for an individual. Access to resources (money, education, etc.) can go a long way to determining one's ability to succeed.
However if we focus on the potency of will-power as a facet of success, there are plenty of examples to draw from.
Thomas Edison is famously quoted as saying that in failing in his first 999 attempts to design a working light bulb, he was really building up to his one success. He also said, "Genius is one percent inspiration and ninety-nine percent perspiration."
I would say that Edison is a nice example of success and will-power's role in achievement.