The head of the US Securities and Exchange Commission, Mary Schapiro, announced on Monday that she would step down from the agency on December 14.
SEC Commissioner Elisse Walter will be designated to succeed Schapiro upon her departure, the White House said in a statement.
"The SEC is stronger, and our financial system is safer and better able to serve the American people - thanks in large part to Mary's hard work," President Barack Obama said.
Speculation had swirled for months that Schapiro would leave soon after the November presidential election.
The announcement marks one of the first departures of Obama's financial regulation team in the aftermath of the election.
Schapiro led the SEC through a major overhaul in the wake of the financial crisis, as it bore the brunt of criticism for its oversight leading up to the crisis and for failing to catch now-convicted Ponzi schemers Bernard Madoff and Allen Stanford.
In the past two years, the agency has logged record enforcement actions, including 735 in the 2011 fiscal year and 734 in 2012, it said in a statement announcing Schapiro's departure.
The SEC has also been bogged down with major rules that the 2010 Dodd-Frank financial regulation law required it to write, many of which are still in process.
"I've been so amazed by how hard the men and women of the agency work each and every day and by the sacrifices they make to get the job done," Schapiro said in the statement.