In announcing the appointments, Mr. Obama was harshly critical of the “disdain for regulation” shown by regulatory agencies in recent years and said the country needed “regulatory agencies ready and willing to enforce the law.”

He pledged to remake the financial regulatory system to adapt to the challenges of a new century. “We will be releasing a very detailed plan on how that regulatory upgrade will take place,” he said.

Mr. Obama also called for a shift in ethics on Wall Street. “We can have the best regulators in the world, but everyone is going to have to ask themselves, not only is this profitable, not only will it lead to a big bonus, but is it right?” he said. “Does it conform to higher standards in terms of how we operate?”

In addition to serving at the S.E.C., Ms. Schapiro was chairwoman of the Commodities Futures Trading Commission during the Clinton administration, an independent agency created by Congress to regulate trading in commodity futures and the option markets. Her service at both agencies could suggest that Mr. Obama is considering combining the two regulators, a structure long supported by many experts to streamline market oversight.

Ms. Shapiro, who would be the first woman to head the S.E.C. for a full term, said that the current crisis on Wall Street “requires an aggressive, systemic response” to restore trust and protect investors. She pledged forceful enforcement of current law and said “thoughtful reform of our regulatory structures” would be her top priority.

The selection of Mr. Tarullo to fill one of two vacant seats on the Fed’s board, which is also subject to approval by the Senate, will allow Mr. Obama to begin making his mark on the nation’s bank. All of the current board members, including the chairman Ben S. Bernanke, were hand-picked by President Bush.

On Friday, Mr. Obama is expected to announce that Representative Ray LaHood, a Republican from Illinois, will be his transportation secretary.