![Walter Zable](https://i2.cdn.turner.com/money/galleries/2009/fortune/0910/gallery.8_over_80.fortune/images/walter_j_zable.jpg)
Age: 94
Job title: President, CEO, Cubic Corp.
Truman was president when Zable founded the San Diego defense technology company in 1951. Zable, a college football Hall of Famer (he played for William and Mary), still works five days a week -- and has no plans to retire. Every morning he rides a stationary bike or uses weights in his home gym.
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