The Office of Constable is mandated by Article 5, Section 18 of the Texas Constitution, which states that in each Justice of the Peace precinct, a Constable shall be elected.

A Constable is a licensed, commissioned peace officer, elected by county constituents every four years for a particular area (Precinct) of that county. Each Constable’s Office is a separate and unique law enforcement agency, independent of all other county departments, elected officials, and law enforcement agencies.

In accordance with the Texas Code of Criminal Procedure, Constables have the same duties and powers as any other peace officer, such as municipal police and Sheriffs, and may enforce all criminal laws, traffic laws, and conduct criminal investigations. In addition, by statute, Constables must serve all warrants, precepts, and civil process lawfully directed to them. Therefore, the Constable is the chief process server for the Justice Court. Constables are required by law to be present, or ensure one of their Deputy Constables are present, during hearings held by the Justice of the Peace.

To meet the challenges and demands of taking on the full responsibilities of being a peace officer as well as the added liabilities of processing civil cases, all Texas Constables and Deputy Constables MUST be licensed by the Texas Commission on Law Enforcement, attend and complete a police academy, fulfill all ongoing continuing education requirements for peace officers, and completed bi-annual training specific to civil process.

The Constable is the oldest law enforcement position in the world, first mentioned in France at the beginning of the 5th century, where it was known as the Count of the King's Stables. By the turn of the 6th century, the Constables were the Chief Household Officers and commanded the King’s Armies in the King's absence. In the year 871 AD, King Alfred of England, declared the Constables to be the highest judge of military offenses and in matters of chivalry and honor. The Constable was also named by the King to be the supreme arbitrator in tilts, tournaments, and martial displays. Becoming noted peacekeepers under King William "The Conqueror" in 1066, the Constable and their responsibilities were expanded with the adoption of the Magna Carta, which became the pattern for most of the world's constitutions and described Constables for the first time in written law.

In Texas on March 5, 1823 Constable Thomas Alley was appointed in Stephen F. Austin's original colony and sworn in by Judge John Tumlinson. Later, another Constable was sworn in by Judge Tumlinson, thus making the two Constables the first law enforcement officers in Texas. The office of Constable was later written into law in the Texas Constitution, stating the Constable would be elected by the people in each area, known as precincts. In Galveston County, all Constable’s Offices trace their origins back to 1838, when the county of Galveston was formally established.