The director of the District’s child welfare agency resigned Monday, ending his three-year tenure a week after a court-appointed monitor delivered a mixed review of the agency’s progress.

Roque R. Gerald’s resignation will be effective at month’s end, said agency spokeswoman Mindy Good.

“Although this was one of the most difficult decisions I’ve had to make in my professional life, it stems from a personal sense that I need to pursue new horizons,” Gerald wrote in an e-mail to his staff.

Former mayor Adrian M. Fenty (D) appointed Gerald, an agency veteran, to lead the Child and Family Services Agency in July 2008, seven months after the discovery of the four slain daughters of Banita Jacks threw it into crisis.

A social worker at the school attended by one of Jacks’s daughters had alerted the agency to potential problems in the Jacks household, but no one intervened until after the girls’ bodies had rotted for months in the bedroom of a Southeast rowhouse.

D.C. Council member Tommy Wells (D-Ward 6), who oversaw the agency as chairman of the human services committee during most of Gerald’s tenure, credited him with clearing a backlog of cases that built up after the Jacks revelations. “He managed resources to urgency in a way that his predecessors did not,” Wells said.

Under Gerald’s tenure, the child welfare agency has avoided another public crisis, but lasting reform has been elusive. It has been the subject of a federal class-action lawsuit for two decades. And although the city agreed to an exit plan in December, the monitor’s report released last Monday indicated that the agency is far from meeting the conditions necessary to do so.

The report, which evaluated the agency’s performance in the second half of 2010, was particularly critical of Mayor Vincent C. Gray’s proposed cuts to the agency’s budget that would affect funding for mental health services, substance abuse treatment and community groups that aid troubled families.

At a council hearing on the agency’s budget last week, member Jim Graham (D-Ward 1) criticized the agency’s “top-heavy” management — in particular, Gerald’s proposal to cut funding for key programs without taking a close look at his own staffing needs. Gerald did not attend the hearing last week, Good said, because he was participating in a two-week trip to the former Soviet Union as part of an effort to develop child welfare systems there.

Graham’s criticism was echoed in a report prepared by a Gray transition team, which cited the agency’s “weak management and top-heavy agency structure.” But Graham, who succeeded Wells as the agency’s chief overseer, praised Gerald on Monday as “well informed, very articulate” and “a loss” for the agency. “I rather wish he would have stayed,” he said. “By and large, he was a pretty fine director.”

Gerald’s departure did not come as much of a surprise to most observers. Like many Fenty-appointed agency directors, he was allowed to keep his job on only an interim basis — far from a vote of confidence from the new administration.

“I think that the mayor definitely wants his own person in the position, and that’s understandable,” Wells said. Gerald declined to comment Monday.

Aside from critiquing the agency’s management, Gray’s transition team highlighted a broader concern often leveled by child advocates about the agency: that it does not do enough to prevent abuse and keep children in the care of loved ones before resorting to “the expensive and harmful current practice of unnecessarily removing children from their birth families.”

Deborah Shore, executive director of Sasha Bruce Youthwork, said it will be up to Gerald’s replacement to improve the city’s record of preventing abuse and neglect so foster placements aren’t necessary. “There is so much more that could be done,” she said.

Matthew I. Fraidin, a professor at the University of the District of Columbia’s law school who studies child welfare issues, said the agency’s next leader needs to “run an agency that doesn’t take kids who don’t need to be taken.”

“Mayor Gray is on notice. Kids are really having their lives torn apart,” said Fraidin, who advised the transition effort.

In his e-mail to staff, Gerald said that he had left “a strong agency, with excellence in some areas and also challenges in other areas but with a solid framework to achieve the goals and mandates that face us.

“Words cannot express my gratitude and pride in what you have accomplished,” he wrote. “Stay the course.”