As Maryland-National Capital Park Police Chief Darien Manley prepared to leave the force Tuesday after 24 years, an unlikely memory stood out in his mind as he recalled rewarding moments in his career.

“Some of the proudest moments of my time, particularly as chief, were during recent years when we’ve gone through these very difficult budget discussions,” he said, mentioning proposals to merge the Montgomery County division of park police, a state agency, with the county-run Montgomery County Police Department.

The proposal, which County Executive Isiah Leggett (D) introduced in 2010 as an effort to repair a $300 million budget shortfall, was voted down by the County Council and criticized by residents at public hearings.

“Hearing the volumes of people coming out to testify in favor of keeping a separate, independent park police agency was so rewarding to me,” he said. “It really helps you feel like you’ve fulfilled the mission; you feel like you’ve served your community well, and you feel appreciated for the service you provide.”

Beginning his career as a patrol officer in 1988, Manley rose through the ranks at a deliberate pace, taking posts in nearly every branch of the department.

From 1993 to 1999, Manley worked in the department’s investigative section, graduating in the first class of the Drug Enforcement Administration’s National Drug Enforcement Officers Academy in March 1994. He spent time in the department’s communications and technology section before making captain in 2005, becoming an assistant chief in the Prince George’s County division of park police.

“The only position I didn’t fill was in our special operations section, the mounted and motorcycle patrol unit,” Manley said. “When you work in those different positions, you really get to appreciate what can be expected of every section; what their strengths and resources are and how to best apply that to meet our mission.”

The experience paid off, said Mary Bradford, director of the parks department, who promoted Manley to chief of the Montgomery County division of park police in 2009.

“Commander Manley was at that time one of several applicants for the position, and I was struck by the fact that, everywhere he worked before, everybody had nothing but superb things to say about him,” Bradford said. “He has that rare combination of strength, kindness and professionalism.”

Manley oversees about 90 sworn officers and 20 support staff in the county division, which has a jurisdiction of more than 418 parks.

Manley, 46, also brought to the position an understanding of the role of park police as ambassadors to the community, said Bob Colvin of Silver Spring, who has volunteered for the department since 1997.

“He always came to address the group whenever a new volunteer came on board and he has always been willing to work with us,” Colvin said.

Manley acknowledged community relations as key to the success of a park policing agency. Even more so than with county officers, park police are constantly interacting with residents, he said.

“Really, that is our ultimate goal, the satisfaction and perception of safety in the parks,” Manley said. “We want people to come to our parks because they are a tremendous resource and it would be its own crime for people not to want to use that.”

Manley will resign from the department effective May 1 to pursue a more behind-the-scenes role in the Maryland State Highway Administration’s division of communications, where he plans to put his experience integrating new radio technology for park police to new use.

The job also will have personal benefits for Manley, who lives in Baltimore with his wife and two sons, ages 11 and 14.

By Tuesday, the parks department will announce an interim chief from among the ranks of the Montgomery and Prince George’s county divisions of the park police, Bradford said.