“Most of the arguments made by the bankers and the I.I.F. in particular are just fallacious,” says Martin Hellwig, an economist and a director of the Bonn branch of the Max Planck Institute.

Even some of Mr. Ackermann’s peers in banking are uncomfortable with his positions. One senior European banking executive said he thought Mr. Ackermann’s zealous defense of banking interests failed to take public opinion into account. Like many ordinary Americans, many Europeans say they are paying the price for the excesses of bankers.

“As an industry, we have a reputational problem and we need to be aware of it and manage it properly,” says this banker, who did not want to be quoted by name for fear of damaging his relationship with Mr. Ackermann.

THE twin towers of Deutsche Bank punctuate the skyline in this city of bankers. They stand as a monument to a bank that was founded in Berlin in 1870 to ease trade with overseas markets, and it is now among the largest banks in the world. Deutsche Bank operates in more than 70 countries and in virtually every corner of finance.

The man who runs this giant has neither the star quality of Jamie Dimon, the head of JPMorgan Chase, nor the polarizing power of Lloyd C. Blankfein, the head of Goldman Sachs. But in Germany, Josef Ackermann is a household name. And although admired by many, he has also become a lightning rod for public hostility toward banks. His name springs to mind for protesters when they look for a banker to demonize.

So it might come as a surprise that in person, Mr. Ackermann comes across as soft-spoken and almost a bit shy. That’s all the more startling because he rose to the top of Deutsche Bank in 2002 after overseeing its investment bank, which isn’t known for shrinking violets.

In an interview late last month high in Deutsche Bank’s headquarters, surrounded by a few examples of the bank’s collection of modern art, Mr. Ackermann portrayed himself as a man who enjoys the simple pleasures. During his rare moments of leisure time, he likes to hike in the Alps in Switzerland, his native country, or browse in bookstores on Fifth Avenue in Manhattan. His bank has a large operation on Wall Street — indeed, it helped inflate the American mortgage bubble — and he keeps an apartment near Central Park.