Avi Schick’s foray into the world of economic development has been swift. Less than two years ago, Mr. Schick, 41, was a deputy in the state attorney general’s office, the lead prosecutor on Eliot Spitzer’s suit against former New York Stock Exchange Chairman Dick Grasso.

A longtime attorney, today he sits as president and acting CEO of New York State’s powerful development agency, with control over numerous multibillion-dollar projects such as the redevelopment of Pennsylvania Station, the Javits Center expansion and the Atlantic Yards project in Brooklyn. With a new administration in Albany and the top position vacant following the recent resignation of the Empire State Development Corporation’s co-chairman, Patrick Foye, a well-connected Mr. Schick is pushing to make his temporary role at the agency’s top a permanent one, according to people with knowledge of his plans.

Reviews of his 15-month tenure as ESDC president, a key oversight position, are mixed as he has formed powerful allies and a set of detractors.

His supporters, Assembly Speaker Sheldon Silver among them, speak of an intelligent, active, competent official who has been a highly effective administrator for the projects in his purview.

His critics—who include numerous government officials, business executives and others who have worked with him—paint almost the inverse picture, claiming they find Mr. Schick forceful, uncompromising and often slow-moving, to the point where having a working relationship with him becomes difficult. Comparisons to the steamroller model of Mr. Spitzer, his former boss, are myriad.

Mr. Schick began emerging in the public’s view about a year ago, when he appeared at a City Council hearing on downtown. Reading a brief statement, he announced that Governor Spitzer would reinvigorate the Lower Manhattan Development Corporation, an agency Governor Pataki had left to dissolve and Mr. Spitzer had criticized in his 2006 campaign. Mr. Schick, already serving as one of two top officials at ESDC, was then appointed chairman of the reborn Lower Manhattan agency, giving Mr. Spitzer a presence downtown.

After that April hearing, Mr. Schick quickly assumed the position of the state’s go-to guy on a multitude of issues, spanning from the Performing Arts Center planned for the World Trade Center site, to the administration of tens of millions of dollars in grants, to wooing financial titan Merrill Lynch to remain in a location downtown.

A physically imposing Orthodox Jew from Brooklyn, Mr. Schick is cordial and warm in casual conversation, noticeably fidgeting his legs as he sits and talks with a confidence about his work. The posts of LMDC chairman and ESDC president, which also includes overseeing the $4 billion-plus Atlantic Yards project in Brooklyn and the possible use of eminent domain for Columbia University’s West Harlem expansion, keep him tied to his work, so much so that he has said he’s added a visible set of gray hairs to his previously jet-black beard.

His tangible successes, his associates and advocates say, include helping substantially enhance a bid to keep Merrill Lynch downtown and reaching a compromise agreement over the Survivors’ Staircase in the World Trade Center site, transporting it into storage before it will be moved to the memorial museum to rise at Ground Zero. The New York Landmarks Conservancy was delighted with his work, and is planning to give Mr. Schick an award next month.

Such actions and advocacy downtown have earned him plaudits from one of the most powerful men in the state, Mr. Silver, the Assembly speaker, who said he has a close relationship with Mr. Schick.

“I think he’s been very effective,” Mr. Silver said. Should Mr. Schick be in the running for the ESDC chairmanship, Mr. Silver said he would back the move. “I would absolutely support it because I’ve seen him work 24 hours a day, literally 24 hours. He’s done very well.”

The developers of Atlantic Yards, Forest City Ratner, also give high marks to Mr. Schick, with CEO Bruce Ratner praising him for his intelligence and competence.

“He’s got a combination of legal ability, leadership and also being able to pull together both lawyers, agencies and the private sector,” Mr. Ratner said. “Compared to other people I’ve worked with in government, he’s on the very, very top.”

Still, Mr. Schick seems to have a large set of detractors, particularly surrounding his dealings in Lower Manhattan. Numerous officials from multiple spheres of government, downtown residents, people in the business community, and others who have worked with him claim, in often caustic terms, that Mr. Schick has carried a prosecutor’s mentality with him to his job, working poorly with others and rarely yielding in his positions, slowing progress on projects.

“He’s impossible to deal with,” said one former government official. “There’s no sense of collegiality or team spirit.”

Officials and people who have worked with him, who insisted on anonymity given the powerful post Mr. Schick currently has and could have, point to his handling of downtown’s Deutsche Bank building deconstruction since a fatal fire last summer as an example of his unnecessarily argumentative nature. Over the months that followed the August fire, Mr. Schick engaged in numerous battles, often public, with the Environmental Protection Agency, repeatedly attempting to loosen the heavy regulations on the tower despite resistance from Mayor Bloomberg, U.S. Representative Jerrold Nadler, members of the community and others.

The E.P.A. held the line and ultimately won many of the fights, and those involved with the deconstruction say Mr. Schick’s resistance slowed the project down substantially. He once said deconstruction would begin by November 2007, but today the building still stands the same height as it did last summer, though abatement work is under way.

“The prosecutorial lawyer’s approach has impeded the ability to reengage in the demolition of the Deutsche Bank building,” said an official involved in redevelopment downtown.

Others say delays in downtown reconstruction, which happened both before and after Mr. Spitzer took office, are extremely frustrating, and the state has not done enough to avoid them.

People familiar with plans note a recent idea brought forward by Mr. Schick to possibly move the Performing Arts Center slated for the World Trade Center site to the above-ground site of the Fulton Street transit hub being built by the Metropolitan Transportation Authority. While the idea is just that—not yet a proposal—those people criticized the concept as one that would further slow development at the World Trade Center site.

Mr. Schick’s position at ESDC was newly created by Governor Spitzer, as the former governor took the job of one man, under the Pataki administration, and divided it up to have an upstate chairman, an upstate president, a downstate chairman, formerly Mr. Foye, and a downstate president, Mr. Schick.

Now more than a year since Mr. Spitzer created it, this division is the source of much criticism by business leaders and elected officials, who say both ESDC’s leaders and clients are hamstrung by the lack of a clear power structure. The structure led to sparring between Mr. Schick and Mr. Foye, who divided up projects and who both reported to the governor, according to multiple people familiar with the organization.

“They ended up effectively having three people in charge of economic development, and having very different visions of what should be done,” said the president of the Partnership for New York City, Kathryn Wylde, who has pushed for more effective governance at ESDC.

“There is no strategic economic development plan for the state—there’s no way to set priorities or manage them,” she said. “It’s irrelevant what individuals you put in if you don’t fix the structure.”

The Paterson administration has thus far been mum on its thinking regarding ESDC leadership, though the state is said to be considering a number of individuals to replace Mr. Foye. The chairmen of both the State Senate and Assembly committees that oversee the ESDC, Senator John Flanagan and Assemblyman Richard Brodsky, said they would rather see one person in charge of development statewide than the current model.

As for Mr. Schick, who is said to be in the running for the downstate chairmanship, his spokesman issued a brief statement saying he is “honored to continue to be of service.”