President Bush's choice to head the besieged Securities and Exchange Commission, investment banker William H. Donaldson, is a Wall Street figure who also knows the halls of power in Washington.

Donaldson is co-founder of Donaldson, Lufkin & Jenrette, a household name among investment banking firms. He was chairman and chief executive officer of the New York Stock Exchange in the early 1990s.

But unlike SEC Chairman Harvey Pitt, who came to government as a securities lawyer with Wall Street clients and resigned under fire last month, Donaldson has experience in the political arenas of the White House and State Department in previous Republican administrations. Pitt's only previous government work had been at the independent regulatory SEC, where he was general counsel from 1975-78.

Though Donaldson could be expected to show greater political finesse than Pitt, who failed to shield Bush from the fallout from a year of corporate scandals, he is known for a colorful candor. That's the quality that contributed to outgoing Treasury Secretary Paul O'Neill's slide from grace in the Bush White House.

Donaldson showed a folksy side at the White House Tuesday as Bush announced his nomination. Referring to the government's obligation to continue to crack down on corporate malfeasance, he said: "As my mother used to say many years ago: "It's time for all of us to pull up our socks."

Shortly before Donaldson took over as chairman of the New York Stock Exchange in January 1991, he described the raging bull market of the 1980s as "a somewhat ribald party" that left the securities industry — and the U.S. economy — with a severe hangover.

And the Wall Street executive whose job it was to rebuild the Street's reputation for fair dealing after the 1980s, once decried the "chauffeured limousines lined up outside fancy, new glass towers, while the homeless congregated in Grand Central Station and lavish Park Avenue parties that made headlines while the lines lengthened at the soup kitchens."

A native of Buffalo, N.Y., Donaldson's first job on Wall Street was at the old brokerage G.H. Walker & Co., run by former President George H.W. Bush's uncle Herbert Walker. Donaldson was a classmate of the former president's brother, Jonathan, at Yale University and is friends with the Bush family.

During the Nixon and Ford administrations, Donaldson was counsel to Vice President Nelson Rockefeller and undersecretary of state with then-secretary Henry Kissinger.

Donaldson also holds corporate and academic credentials, as founding dean of the Yale School of Management and having taken the helm of insurance giant Aetna Inc. in 2000 amid pressure from shareholders seeking improved relations with patients and doctors.

Donaldson was a Marine who served from 1953 to 1955 in Korea as a rifle platoon commander. A Yale graduate who received his MBA from Harvard, Donaldson is a chartered financial analyst and director of a number of public and private corporations and charitable groups.