Alexandria City Manager Philip G. Sunderland said last night he was stepping down as the city's top executive after four years of directing the affairs of the historic municipality.

Sunderland, who served for 14 years as the Alexandria city attorney before becoming city manager, was overseeing a budget of $500 million and a workforce of more than 2,500.

"It's sad for us. . . . I tried to talk him out of it, but his mind was made up," said Alexandria Mayor William D. Euille (D), who announced Sunderland's departure last night at a City Council meeting. "It's a tremendous loss for the city of Alexandria."

Euille said that city officials would immediately launch a national search for a city manager. He said they hope to make a selection by Sept. 30. Sunderland is expected to remain in his post until a successor is chosen.

At last night's meeting, Sunderland said he was "going to take some time," but he did not elaborate. He issued a statement earlier in the day saying he wanted to pursue other professional interests.

"I have had 18 wonderful years with Alexandria, lawyering and managing, and experiencing local government from just about every angle," he said in the statement. "But now it's time to pursue the personal and professional interests that the demands of these jobs have not permitted. Among many other things, my desire is to teach, ideally at the college or law school level, and to return to lawyering."

Vice Mayor Redella S. "Del" Pepper (D) said that city officials have long known -- even when Sunderland was appointed manager in March 2000 -- that he yearned to leave city government and try another career.

"We kind of always knew he wanted to move on," Pepper said. "Even when we hired him in 2000, he had said then that after a certain number of years he wanted to pursue a career in teaching. I think that time has come."

Neighborhood activists -- including some who had clashed with Sunderland -- said they were surprised.

"I'm shocked. He'll be hard to replace," said Katy Cannady of the Alexandria Federation of Civic Associations.

During his tenure, the city launched initiatives on open-space preservation and affordable housing. The city also paved the way for the move of 7,100 employees of the U.S. Patent and Trademark Office to a new, five-building campus in the area near the Eisenhower Metro station.

In addition, the city's crime rate has decreased, with the city's most serious crimes falling to their lowest levels in 34 years, officials said.

Sunderland's tenure was not without controversy. Sunderland came under heavy fire in 2001 for the city social service system's role in the death of Katelyn Frazier, 3. The toddler died in December 2000 while in her mother's apartment, though she was in city custody.

The case received extensive scrutiny, in part because Sunderland at first said that he thought the city had handled the case properly and that he would not discipline staff members. Sunderland later apologized and placed two employees involved on administrative leave with pay.

Before his appointment as city attorney in 1986, Sunderland was a partner in a public-interest litigation law firm in the District, where he litigated in federal and state courts, specializing in environmental, civil rights and employment law. Before that, he served in the Office of General Counsel for the U.S. Department of Health, Education and Welfare.