The steelworkers’ union is one of the nation’s most muscular, helping to deliver Pennsylvania and Ohio to Mr. Obama, pushing for Buy America provisions in the stimulus package and pressing politicians to renegotiate the Nafta trade agreement. With 800,000 members, it is larger than the U.A.W., representing not just steelworkers, but paper, aluminum, oil, chemical and rubber workers.
In the early 1990s, Mr. Bloom, who graduated from Wesleyan University, was co-founder of the boutique investment firm Keilin & Bloom, He specialized in transactions on behalf of major unions, including the steelworkers, auto workers, Air Line Pilots Association and International Brotherhood of Teamsters.
Before that he was a vice president at the investment banking firm Lazard Frères & Company, where he worked on mergers and acquisitions, restructuring and divestitures, with a focus on union-related transactions.
Mr. Bloom did not return several telephone calls, and a union spokesman, Gary Hubbard, said Mr. Bloom was not giving interviews.
Michelle Galanter Applebaum, who got to know Mr. Bloom in the 1990s when she was a managing director at Salomon Brothers, said he was different from other investment bankers because of his unusual interest in helping workers, unions and beleaguered industries.
“He felt he could play a meaningful role of fixing it from the inside,” said Ms. Galanter Applebaum, who is now managing director of Steel Market Intelligence. “He is a passionate, committed guy, totally idealistic.”
For all his accomplishments in the steel industry, Mr. Bloom is not well known in the auto industry. The Treasury Department has not been clear about exactly what role he will play. After the giant steel makers the LTV Corporation and Bethlehem went bankrupt early this decade, Wilbur L. Ross Jr., the financier, sought to acquire their steel mills and employ many of their workers, without having to pay for retirees’ health coverage.
Mr. Bloom, working with Mr. Gerard, negotiated with Mr. Ross to form a VEBA, a Voluntary Employee Beneficiary Association, in which a percentage of the profits from Mr. Ross’s company, International Steel Group, would go to the VEBA to help finance prescriptions for the retirees.
“I found him first of all very, very pragmatic, not overly ideological,” and “a very, very good negotiator,” Mr. Ross said.
He added that Mr. Bloom, who has moved seamlessly between labor and corporate finance — was not one to make lopsided deals.
Mr. Trbovich, the former steelworkers’ official, said that once when Mr. Bloom was negotiating with Mr. Ross, “he laid out a whole different way to look at a financing proposal than the one that was under discussion.”
“Ross listened attentively, and when Ron was done, Ross said, ‘The force is with the young man,’ ” Mr. Trbovich said.
Mr. Gerard, the union’s president, said Mr. Bloom would represent not the U.A.W.’s members, but the Obama administration in seeking to assure a future for the nation’s automobile industry.
Mr. Gerard told of a meeting with 40 bankers in which a highly paid McKinsey consultant put together a business plan for a steel company “that was going to beat the hell out of the workers.”
“Ron asked, ‘Doesn’t this number belong here and doesn’t that number not add up,’ and Ron slowly dismantled this guy’s business plan to show it was a house of cards,” Mr. Gerard said.
“Ron knows how to separate the bull from reality.”
Louis Uchitelle, Michael J. de la Merced and Bill Vlasic contributed reporting.