But the deal benefited from a wave of electricity deregulation, and backers of the merger argued that the new company would be well-positioned to sell power in markets across the country as states opened their electricity markets up to competition.

The merger created a job for John Rowe, the CEO of Unicom who went on to become CEO of the merged company, Exelon. And Emanuel and Rowe have remained personally friendly.

After the Nov. 4 election, Emanuel was shopping in a bookstore when he called Rowe on his cell phone, asking for guidance on whether he should take the top White House staff job, according to The Washington Post.

Emanuel’s elevation to the White House comes at a pivotal time for the company he helped create. Exelon is now involved in a hostile takeover bid for the assets of NRG Energy, which would create the nation’s largest power company. NRG rejected Exelon’s initial bid of more than $6 billion, calling the offer too low.

The deal potentially faces a host of regulatory and government approvals, and industry insiders will be watching to see that Exelon is treated fairly by the Obama administration.

Donors affiliated with Exelon gave Obama’s presidential campaign more than $197,000, according to the Center for Responsive Politics.

“The Obama administration seems to be trying to set a high ethical standard,” said Sue Kelly, vice president of policy analysis and general counsel at the American Public Power Association. “We’d want to make sure that this merger received the close scrutiny that it deserves.”

Executives at Exelon declined comment.

An Emanuel representative said that Exelon won’t get any special favors from the White House. “Serving the American people and President Obama is Congressman Emanuel’s only priority,” the representative said.

Another key deal that Emanuel worked on at Wasserstein also had Chicago roots: the sale of SecurityLink, the home security unit of SBC Communications, to the Chicago-based venture capital fund GTCR Golder Rauner.

Emanuel’s old boss, billionaire Wasserstein, who is now chairman and chief executive of Lazard Ltd., praised the politician’s business skills in a statement.

“Rahm did a great job for our firm,” Wasserstein said. “Energetic and extremely popular in the Midwest, he had a keen understanding of the interplay of regulatory aspects and corporate activity in financial advisory work, particularly in the utility and banking industries.”

In 2000, Emanuel added to his private sector résumé, accepting an appointment by President Bill Clinton to the board of directors of Freddie Mac, a position he held until he began his campaign for Congress.

He served at Freddie Mac at a time when the mortgage giant was later found to have misstated its annual revenue. Freddie Mac and its corporate sibling, Fannie Mae, have been widely blamed for playing key roles in the mortgage market meltdown that triggered the current financial crisis.

A spokeswoman in Emanuel’s congressional office said his business career is something that Emanuel has already been drawing upon.

“When Congress considered the financial crisis in September, Rep. Emanuel used his knowledge of the financial industry to help protect taxpayers and significantly strengthen the economic rescue package,” said Emanuel’s spokeswoman, Kathleen Connery. “His experience in government and business will be a tremendous asset as he works with President-elect Obama to help get our economy back on track."