The county judge is the most visible official in county government. Often thought of as the county's chief executive officer, a county judge has broad judicial and administrative powers, including serving as the presiding officer of the county's policy-making body, the commissioners court. Referred to as "chief justice" by early Texas constitutions, the current office of county judge was established by the Texas Constitution of 1876.

County judges are elected on a countywide basis. Originally, the term of office for this position was two years but in 1954 the Texas Constitution was amended to increase the term of office to four years. Article V, Sections 15-18 of the Texas Constitution contains the legal basis for the office of county judge as we know it today: "There shall be established in each county in this state a County Court, which shall be a court of record; and there shall be elected in each county, by the qualified voters , a county judge, who shall be well informed in the law of the state; shall be a conservator of the peace; and shall hold office for four years, and until his successor shall be elected and qualified..."

Although they must be well informed in the law, there is no requirement for county judges to have a formal legal education or a licence to practice law. After election, however, a county judge is required to attain thirty hours of judicial education during their first year in office and sixteen hours every year thereafter in order to remain up to date regarding new laws and procedures related to their judicial responsibilities.

The county judge resides over the constitutional county court. While responsibilities vary from county to county, a judge may consider criminal, civil, probate, juvenile and mental competency matters. In larger counties, county courts-at-law have been created with separate judges to handle the large amount of work these cases generate. Also, in those counties in which the judge has judicial responsibilities, the judge has appellate jurisdiction over matters arising from the justice courts.

The county judge is the presiding officer of the commissioners court and is required by law to perform this function when present. In the judge's absence, any commissioner may preside over the court. It is incumbent upon the county judge to carefully abide by statutes requiring that meetings of governmental bodies be open to the public.

The judge is also a voting member of the commissioners court and works with the other four members of the court to approve the county budget and exercise administrative authority over county government operations. County judges do not have autonomous authority to set the business of the commissioners court or decide what motions will be heard; the entire court makes these decisions.

A major responsibility of the commissioners court relates to setting the county budget. In counties with a population under 225,000 the judge serves as budget officer of the commissioners court. During budget development, the judge along with the commissioners considers the funding necessary for the other county offices to carry out their duties.

County commissioners courts are responsible for many other functions, including: supervision and control of the county courthouse, county buildings and facilities; determining county tax rates; and filling vacancies in elected and appointed positions. Additionally, commissioners courts are responsible for building and maintaining county roads and bridges; letting contracts in the name of the county; administering and making key decisions regarding libraries, county hospitals, welfare programs, parks and playgrounds.

County judges perform a wide range of other administrative duties. These responsibilities include conducting hearings for beer and wine license applications, calling elections, posting election notices, and canvasing the election returns. The county judge also serves as the county's Emergency Management Director and has the authority to designate an Emergency Management Coordinator to serve as an assistant for emergency management issues.

The county judge may also represent the county at ceremonial occasions and on various boards and committees such as regional councils and governments. The may also serve as a member of the governing body or as an officer or director of another entity, except as pubilcly traded corporation or a subsidiary affiliate, or subdivision of a publicly traded corporation that does business with the county.

The broad range of responsiblilities of county judge makes this office a very important office in county government. With a judge's judicial, administrative and ceremonial duties, it is also a very high profile position.

Because the Texas constitution limits each county to only one county court, county courts at law are created by statute in larger counties, primarily to aid the single county court in its judicial functions. The legal jurisdiction of these special county-level trial courts can vary considerably and is established by the specific statute that created each court.