(FORTUNE Small Business) – At the age of 24 he took his $7,000 savings and has since transformed it into a 650-store, $1.3 billion sartorial empire.

How he did it

A steady growth plan, deep discounting, and an aggressive marketing campaign helped, but Zimmer's "I guarantee it" ad lib during a 1985 commercial turbo-boosted his profile and profits.

--MACCABEE MONTANDON