Christine M. Coulter has become Philadelphia’s first female police commissioner.

Her title is “acting police commissioner” while the city searches for a replacement for Richard Ross, who resigned abruptly Tuesday, Mayor Jim Kenney announced.

But the promotion is still historic. The last woman to come close to the top job was Patricia Giorgio-Fox, who in 2002 became the first woman named a deputy commissioner.

Among all women now leading police departments in the United States, Coulter is in charge of the largest, said Kym Craven, executive director of the National Association of Women Law Enforcement Executives. Other women in top spots around the country include Carmen Best, police chief in Seattle, and Danielle Outlaw, police chief in Portland.

Coulter, 57, has been on the force for nearly three decades in all sorts of roles across the department. But she stood out early on, said SEPTA Transit Police Chief Thomas J. Nestel III, who was on the city force when he met her.

She was a “shining star” who valued professionalism, Nestel said.

However, it wasn’t immediately apparent that Coulter might rise to the highest levels of the department, he added.

“Police officers don’t necessarily become great commanders. It’s about evolving as your career continues,” he said.

“She’s a great choice” for the top job, Nestel said. “She’s a really good person and certainly has the department’s best interest in mind."

It wasn’t clear if Coulter — who could not be reached for comment — is a contender for the mayor’s final selection.

In 2014, she was promoted to deputy commissioner by former Commissioner Charles H. Ramsey.

Coulter has been an inspector overseeing the Traffic and Central Police Divisions. She was captain of the 16th District in West Philadelphia, a lieutenant in Narcotics, and a sergeant in the East Detective Division. During her rank-and-file days, she served as an officer in the tough 25th District in North Philadelphia.

Most recently, she was the three-star deputy commissioner of organizational services.

“I have full faith in her ability to lead the department during this time of transition,” Kenney said in a statement.

Coulter has a master’s degree in public safety management from St. Joseph’s University, a bachelor’s in organizational management from Eastern University, and an associate’s degree in criminal justice from Community College of Philadelphia.

She is a faculty member in the graduate program of public safety at St. Joseph’s Institute of Criminal Justice and Public Safety Administration.