Founded in 1932, the police department serves the entire island of O'ahu, covering over 600 square miles (1,600 km²) of territory, with just over 900,000 residents (not including military members) and over four million annual visitors. The island is divided into 8 patrol districts which are then subdivided into sectors and beats. The HPD currently has more than 2,500 employees, 2,134 of which are full-time sworn officers. A 2003 Department of Justice report listed The HPD as the 21st largest police department in the nation.

Unlike the other 49 states, Hawai'i does not have a state police agency or individual city agencies; law enforcement is the jurisdiction of the individual county governments. The HPD is nationally accredited by the Commission on Accreditation for Law Enforcement Agencies (CALEA).

In 1840, the Supreme Court of Kamehameha III established the first constitution for the Kingdom of Hawai'i. The constitution paved the way for the Act to Organize the Executive Departments of the Government signed on April 27, 1846. The law created the office of marshal of the kingdom, the highest ranking police officer in the nation. He nominated, instructed, supervised and controlled the sheriffs of the kingdom of which there were four, one for each administrative region of Kaua'i, O'ahu, Mau'i and Hawai'i. Each sheriff administered a corps of constables officially appointed by the four royal governors. Constables wore a distinct police insignia that consisted of a scarlet crown with the initials KIII in honor of Kamehameha III. The insignia was worn on the arm and on a red band on their police hats.

In 1893, the Kingdom of Hawai'i was replaced by the Provisional Government of Hawai'i which quickly deposed the marshal of the kingdom and dissolved the constabulary. In 1894, the newly proclaimed Republic of Hawai'i formed its own police system.

After a few years under the governance of the Territory of Hawai'i, four county governments were established out of the original administrative regions of the monarchy. In 1905, each county was equipped with a police department led by an appointed sheriff. Police officers wore an octagon-shaped police badge similar in appearance to those of other police departments of the period. In the 1920s the badge was redesigned with an eagle on top.

In Hawaii, the Office of Sheriff falls under the Sheriff Division of the Hawaii Department of Public Safety. It is the functional equivalent of a state police department and has the distinction of making Hawaii the only U.S. state without an officially named state police department and one of two with a statewide Sheriff's Department (the other being Rhode Island). Although the Sheriff Division's jurisdiction covers the entire state, its primary functions are judicial and executive protection, security at the Hawaii State Capitol, law-enforcement at Hawaii's airports, narcotics enforcement, prisoner transportation, the processing and service of court orders and warrants, and the patrol of certain roads and waterways in conjunction with other state agencies.

Additional state-wide law enforcement is provided by the Department of Land and Natural Resources (DLNR) which patrols State lands, State Parks, historic sites, forest reserves, aquatic life and wildlife areas, coastal zones, Conservation districts, State shores, as well as county ordinances involving county parks. The division also enforces laws relating to firearms, ammunition, and dangerous weapons. DLNR officers have full police powers.

In response to a crime wave in the late 1920s as a result of increased racial tensions between whites and local ethnics, Territorial Governor Lawrence M. Judd appointed a Governor's Advisory Committee on Crime. The committee recommended that a police commission be appointed by the mayor of Honolulu whose duty it would be to appoint a chief of police and to supervise the operating of the police department. The committee also advised that the office of sheriff should be retained and charged with the duty of serving civil process, of maintaining the Honolulu prison system and to act as coroner. On January 22, 1932, a special session of the territorial legislature passed Act 1, establishing the Honolulu Police Commission and creating the office of chief of police. Thus was born the modern Honolulu Police Department as it exists today.

After the attack on Pearl Harbor on December 7, 1941, Territorial Governor Joseph B. Poindexter declared martial law and Hawai'i fell under military governance under the Judge Advocate General's Corps. The Honolulu Police Department became a deputized military force. The word "Emergency" was etched above the "Honolulu" on the seven-point star badges of police officers. For the duration of World War II, the Honolulu Police Department was forced to impose restrictions on civil liberties and hand people over for trial by a military judge. Martial law ended after the end of the war in 1945.

Interestingly, the San José State Spartans football team served with the Honolulu Police Department for the duration of World War II; the team had played a game against the University of Hawaiʻi at Mānoa Warriors but were stranded in Hawai'i after the Pearl Harbor attack.