Phoenix was incorporated as a city on February 25, 1881. Law enforcement was handled by Phoenix city marshals and later by Phoenix police officers.

Henry Garfias, the first city marshal, was elected by residents in 1881 in the first elections of the newly incorporated city. For six years, he served as the primary law enforcement officer.

In the early 1900's, the Phoenix Police Department used Old Nelly, the horse, to pull the patrol wagon for officers. Most patrolling, however, was done on foot. The city at this time was only 3.1 square miles with a population of 11,134 people.

Call boxes were used to notify an officer that headquarters wanted him. These were supplemented by a system of horns and flashing lights

 The first Phoenix police officer killed in the line of duty in Phoenix occurred on February 5, 1925. Officer Haze Burch was shot and killed by two brothers on the run from authorities. The men were later arrested when they were found hiding at the Tempe Buttes.

In 1929, patrolmen worked six days a week and were paid $100 a month. The police department moved into the west section of the new city-county building at 17 South 2nd Avenue. The building included jail cells on the top two floors.

In 1933, Ruth Meicher joined the police department as the first female jail matron. The city at this time was only 6.4 square miles, with a population of 48,200. In the year prior, the first police radio system in Arizona was installed for the department with the call letters KGZJ.

The department reorganized in 1950 with four divisions, Traffic, Detectives, Patrol and the Service Divisions. Officers worked 44 hours per week for $288 per month.

In 1974, the Air patrol unit was established initially consisting of one helicopter. A few months later, a fixed wing aircraft and two additional helicopters were added.

Today, the Phoenix Police Department provides law enforcement to 1.2 million Phoenix residents encompassing an area of more than 469 square miles. To accomplish this, the department employs approximately 2,600 police officers and detectives and more than 700 civilian support staff personnel.