One such example is Roberto Goizueta, whose work habits at the helm of Coke were vividly described in this book - Greising, David (1989). I'd Like the World to Buy a Coke: The Life and Leadership of Roberto Goizueta.
Roberto Goizueta was leaving his work at 3-4 p.m. daily. He almost never stayed till 5-6 p.m. or even overtime.
He managed to achieve this feat by focusing on three things:
1. capital allocations decisions;
2. people management (he personally made any/all personnel decisions for top 100 people);
3. managing Wall Street/analysts.
Compare this with current breed of CEOs/COOs/etc.