For a man who was supposed to be retiring this spring, Josef Ackermann shows little sign of slowing down. Over the past 18 months, the Swiss-born CEO has guided Deutsche Bank through the financial crisis with aplomb, shifting it from a high-risk proprietary trading shop to one geared mainly toward executing customer orders, all while restoring a healthy level of profitability. And he has done so without the help of a government bailout or capital injection — making Deutsche one of only a handful of European banks not to dip into the public purse.

Ackermann’s success, moreover, resonates well beyond Deutsche. The 61-year-old banker has become a standard-bearer for the industry. As the head of Germany’s only healthy and globally powerful bank, Ackermann enjoys a clout at home that enabled him last fall to persuade Chancellor Angela Merkel not to impose a bonus tax on bankers, as the U.K. government...