Montgomery County Executive Douglas M. Duncan has reshaped the top rung of county government in recent weeks by picking a series of blunt-spoken outside candidates to fill key Cabinet posts, passing over veteran county employees in the process.

The latest selection came yesterday when Duncan named Arthur M. Wallenstein, who runs the jail system for the county that encompasses Seattle, to head Montgomery's Department of Correction and Rehabilitation. The post has been filled for the past year by a veteran county employee who was one of five finalists for the job.

The selection worried some civic activists and union leaders, coming so soon after Duncan (D) chose outsiders to run the police department and the public works and transportation agency. Adding to the sense of change, the school board recently chose an aggressive North Carolina school superintendent to run the vaunted public schools system. Duncan did not have a hand in his selection.

County traditionalists say the Montgomery way of slow, deliberate policymaking is being diluted by the infusion of new blood. But others commend Duncan for chiseling away at an ossified county government.

Internal candidates once held significant advantage over outsiders for Montgomery's top jobs. But Duncan rarely has tapped the county farm system, and now in his second term, he is looking to urban centers for prospects to fill out his Cabinet as he guides Montgomery through its evolution from suburb to sprawling metropolis.

"These people I have brought in are much more plain-spoken, much more open and results-oriented than what you have normally seen in Montgomery," Duncan said. "That's due to the changing nature of the county. People expect us to be more out front of problems than has been the case in the past."

Leading the list of recent recruits is Police Chief Charles A. Moose, who held the same post in Portland, Ore., and Public Works and Transportation Director Albert J. Genetti Jr., whom Duncan hired from the federal government.

Some Montgomery activists and union leaders say Duncan is overlooking a talented pool of county employees well schooled in the way public policy has been made in the suburb. Many believed that Russell E. Hamill Jr., who has been with Montgomery for three decades and filled the corrections job for the last year, should have been selected. Hamill was endorsed by three of the four previous county executives.

"I find it somewhat offensive to say here is one of the best-educated, most into public affairs places in the country, but no one can do the job," said Alice K. Helm, an activist who has lived in Montgomery for 35 years.

During his first county executive campaign five years ago, Duncan called for a general housecleaning at the top ranks of Montgomery government. Upon his election, he fired more than half of the county department heads. His predecessor, Neal Potter (D), fired no one when he took office.

Since then, Duncan has remade his Cabinet with a set of administrators less preoccupied with the consensus-first approach that has dictated the pace and success of Montgomery policymaking for decades. Of the 19 department heads Duncan has the authority to appoint, he has brought in 11 from outside the county.

He first looked within Maryland to fill top jobs, picking his economic development director from Allegany County and his county attorney from Carroll County. Duncan then began tapping candidates from out of state. He chose his recreation director from Elgin, Ill., and his director of library services from Louisville.

Those who support Duncan's appointments say Montgomery is living through a moment when it needs an urban perspective to address such issues as rising poverty, increasing pockets of crime and racial strains resulting from increasing ethnic diversity.

"We have accumulated too many people who are accustomed to the way Montgomery works. They have lost their entrepreneurial spirit," said Jorge Ribas, president of the Montgomery County Civic Federation, an umbrella group for an array of civic organizations.

Moose, the new police chief, said he does not want to ignore the Montgomery way, even if it may not always be practical. "If our constituents want a lot of process, then we will respect that. But people do count on government to make decisions, and in this age of technology when things are moving faster than ever, delays come to look like incompetence."

Wallenstein, 54, received high praise from his former colleagues in King County, a metropolitan area of 1.6 million residents. Colleagues say he is an unlikely jailer -- an erudite, affable administrator who writes elegant book reviews and quotes Shakespeare.

He said he accepted the post that will pay him $118,000 a year in large part because most of his family lives on the East Coast. Among his top priorities is to increase the diversity of his 383-member staff, which he said "must look like our jail population."

"The community I come from is a dead ringer for Montgomery -- growing, diverse and growing in its diversity," Wallenstein said.