The party to celebrate baseball's return to Washington was winding down at Georgia Brown's, and D.C. Mayor Anthony A. Williams had already left the downtown restaurant. With him was Stephen M. Green, the city official who had led the successful negotiations with Major League Baseball.

The two men enjoyed a victory cigar -- not as mayor and aide but as Tony and Steve, buddies since Yale University nearly 30 years ago.

Five years ago, Green was a developer who had never worked in government. Now he finds himself at the helm of one of the most important initiatives of Williams's tenure: the $440 million financing package to move the Montreal Expos to Washington this spring and house them in a new waterfront stadium by 2008.

Green, 49, whose title is special assistant to the mayor for planning and economic development, was one of three city officials who hammered out the District's agreement with Major League Baseball during marathon sessions last month. Now, most days, he appears before two or three community or business groups to tout the baseball project, trying to convince a skeptical public that the stadium will spur development in nearby neighborhoods, create jobs and generate tax revenue to support social programs.

It is by far the most headline-grabbing work Green has done at City Hall but hardly the first time that Williams and Eric W. Price, deputy mayor for economic development, have entrusted him with key decisions. Since joining the Williams administration in February 2000, Green has shaped at least a dozen residential and commercial projects worth more than $2 billion by negotiating with developers over tax breaks, design plans and land-use requirements in an effort to ensure that the projects will revive or stabilize surrounding neighborhoods.

Among the projects: an $800 million plan to redevelop the old convention center site at 11th Street and New York Avenue NW; the proposal to build a $400 million hotel for the city's new convention center; and the $500 million development at Waterside Mall in Southwest Washington for mortgage giant Fannie Mae.

"Whether you love him or not, you have to respect what he has been able to achieve on behalf of the city. He's had his fingerprints on most everything," said Marc A. Dubick, who is managing the $170 million development at the former Wax Museum site on Fifth and K streets NW.

Like Williams, Green believes passionately that public subsidies for private developers -- in the right circumstances -- are key to fighting urban blight and poverty. The plan to use mostly public funds to build the ballpark on the long-ignored Anacostia River waterfront is a product of that philosophy, he argues.

Opponents of the baseball deal, who are working to persuade the D.C. Council to reject it, say the projections of job and tax revenue growth from the stadium are overstated. They see the stadium project as emblematic of the mayor's record in a different sense, arguing that the public subsidy for millionaire team owners and players reflects a tendency to favor business interests over the needs of low-income communities.

In arguing that the stadium will ultimately expand the District's tax base and help the city's neediest, Green defends both the specifics of the agreement and the instincts of his old friend.

"I think I know better than most who the mayor is and what his vision is," Green said. "What drives him is the creation of public value. He has always had an interest in creating public value in the world."

Green and Williams met as undergraduates at Yale in 1976 and shared an off-campus house one year with several other students. The two men say they were drawn to each other's intellect and forged a strong friendship.

They stayed in touch after college as each pursued careers that included stints with community development organizations.

Green built affordable housing for a nonprofit in New Haven, Conn., until Reagan-era budget cuts dried up funding. He then became a for-profit developer, with mixed results, at one point launching a venture with a colleague who later was indicted on fraud charges in connection with a different deal.

Within a few years, the real estate market collapsed. Green said he found himself "undercapitalized and overleveraged," unable to sell or rent his projects for a profit. He liquidated his assets and, in 1993, joined Community Builders Inc., a nonprofit urban housing developer, eventually overseeing more than $50 million worth of projects.

But creditors kept calling, and in 1995 Green filed for personal bankruptcy protection. Green said he and Williams had long conversations about the District that year, when Williams became the city's chief financial officer, and again in 1998 when Williams was drafted to run for mayor.

Soon after he took office, Williams asked Green to join his team.

Initially, Green focused on housing, crafting legislation that offered developers tax incentives to build residential projects downtown and affordable housing citywide. But his portfolio quickly expanded to include commercial and retail projects.

Williams said he and Price call on Green, whose salary is $103,318, for "the very biggest projects, the most sensitive, the most important projects."

Although the baseball deal has been criticized as overly generous, Green has a reputation among developers as a tough negotiator.

He told a team planning to upgrade the Waterside Mall complex in Southwest that the city would not support the zoning and lease terms the team needed unless the project was reconfigured to include apartments and Main Street-style shops. And he insisted on dividing the mall into two sections and reopening a closed section of Fourth Street SW so the riverfront would not be cut off from the residential blocks to the north.

"We went in there thinking we were going to be welcomed with open arms," said Deborah Ratner Salzberg, president of the Washington office of developer Forest City Enterprises. "It was much tougher than anything we had anticipated."

Green also fought requests for additional city funds to support the rehabilitation of the historic Tivoli Theater in Columbia Heights, which was being rebuilt as part of a $40 million shopping and office complex and was already slated for $4 million in aid.

"He's difficult to deal with," developer Joseph Horning said. "When the cost started escalating, he wanted to board [the theater] up."

Horning and Tivoli supporters turned to D.C. Council member Jim Graham (D-Ward 1), who found another $4 million for the project. The renovation is slated for completion in December.

Some developers say privately that Green's attention to baseball in recent months has slowed progress on other projects, notably the redevelopment of the city's old convention center site. Last week, the mayor delayed release of a report that the D.C. Council has requested on whether to reserve space for a large hotel on the site, saying he needed more time.

The convention center project -- involving 10 prime downtown acres -- has been Green's most contentious so far. Last year, a team bidding to develop the site sued the city when it was not selected as a finalist, calling the process unfair and those running it -- Green and D.C. Planning Director Andrew Altman -- unqualified. Although the District denied wrongdoing, it agreed to settle for $5 million so the $700 million development could proceed.

"If one of my subordinates had cost me $5 million, I'd take his marbles away from him," said D.C. Council member David A. Catania (I-At Large), a critic of Green's.

Green says he stuck to his guns as much as possible when negotiating the baseball deal but still had to offer significant incentives to Major League Baseball, which holds a monopoly in deciding whether teams can be moved. "It's not a rational market environment," he said.

The city gave up stadium naming rights in return for annual rent payments, which Green considers less risky because they don't depend on the team's popularity or the sponsor's economic health. The District rejected baseball's request to cap its annual rent at $3 million; rent will start at $3.5 million and escalate over 30 years to about $9 million.

The city will use that revenue -- plus the taxes it will levy on businesses and ballpark tickets, concessions and merchandise -- to pay off the stadium construction bonds.

Opponents say they will use Thursday's public hearing before the D.C. Council to express their outrage at a stadium being financed overwhelmingly by the city to benefit business people wealthy enough to bid $300 million to buy the team.

"This should not be a heavily subsidized, publicly financed stadium," said Ed Lazere, executive director of the D.C. Fiscal Policy Institute. "If the team owners want to come here and want a shiny new stadium, they should build it themselves."

Green says Major League Baseball wouldn't have considered such a scenario, and baseball officials agree.

Speaking to a group of nonprofit developers last week, Green described how stadiums in San Francisco, Denver and Pittsburgh have spurred neighborhood renewal and predicted that Washington's new facility will do the same. He described suburbanites and city residents electing to spend their money on a waterfront dinner and a ballgame rather than a movie and a bite to eat at Pentagon City or Bethesda Row. He talked up the tax revenue from baseball-related hotel visits.

"That's what building a city is all about," he said. "It is about creating a stable pace of revenue so that you have the resources available to provide the services."

But those in the audience remained unconvinced. They said the city should have pushed harder to get Major League Baseball to pay more toward stadium construction. At the very least, they said, Green and his colleagues should demand that stadium jobs pay a living wage and include training for unskilled D.C. residents. Some said the city should have launched a project to benefit the community more directly -- a new housing development, for example, or a jobs center -- as part of a stadium deal.

"Folks need something that they can see and touch," said W. Retta Gilliam, president and executive director of East of the River Community Development Corp., "something to ensure that at the end of the day, the residents are at least able to participate in this quote-unquote renaissance of the city."

Stephen Green, mayor's special assistant for planning and economic development, points to joints in need of work at RFK Stadium, which would temporarily house a D.C. baseball team.