The beginning of Jirkov history is covered in the mist of legends. Historians place the settlement's beginnings in the last third of the 13th century. The popular assumption that Jirkov was founded in 1269 at the instance of King Přemysl Otakar II who had an interest in the colonisation of the large forest areas in the borderlands of his realm is not based on historical evidence. A certain fact is, that there was a Gothic church here as far back as the year 1300 and that Jirkov really was founded as a colonisation settlement on the Bohemian and Saxon borders. The chronicles mention this location several times under the names of Borek or Jurkov between the years 1321 and 1337. The first convincing evidence describing the settlement of Jurkov dates back to 1352. The assumption that Jirkov grew as a settlement round the castle of Borek (later Červený hrádek) found in several later chronicles is now refuted as it has been proven that the castle was founded much later - in the 15th century.
Jirkov was spared from a siege by the Hussite army in 1421. The legend has it that this was due to a dense fog. The castle however was conquered and pillaged.
The following decades are characterised by the townsmen of Jirkov trying to gain the highest possible degree of independence from the feudal lords of the Červený hrádek château. These attempts were to a certain degree successful as the town got certain rights and privileges acknowledged by the kings. The most important was the charter which granted Jirkov the town privileges issued by King Ladislav Pohrobek on 25th February 1455.
These privileges were later confirmed by a succession of other kings; Vladislav II (1507), Ferdinand I (1528), Maxmilian (1570) and Rudolf II who also granted the town the right to use a coat of arms and a town seal. A town brewery started operating in 1480 and it is said that the emperor Rudolf II developed a special fondness for Jirkov beer. It is said that it was an obligatory article at the emperor's dining feasts in Prague.
In the 16th century, the town prospered due to the good care of the aristocratic families who held it. There were 6 guilds active in the town, alum was mined, and as late back as 1597, there was a water supply system in operation in the town. A company of shooters was established in 1544 and was active for over 300 years. In between 1555 and 1595, the system of underground cellars and corridors was created which was used for many purposes; as the brewery's cellars for example. It survives until the present time.
After the Battle of White Mountain (1620) the town lost almost all its privileges and it was repeatedly pillaged by all the armies of the Thirty Years' War. Many confiscations took place in Jirkov, the Lutheran clergy were replaced by catholic priests, and craftsmen from Germany started their activities in the town and soon outnumbered the Czech ones. A period of relative peace did not occur until the 1660s. The town however never achieved the previous level of prosperity. The castle of Červený hrádek, destroyed in the war, was rebuilt into a one-storey baroque chateau with a chapel.
The following century brought at least some calm and economic increase; under the rule of Jindřich František of Rottenhahn and Jiří Buquoy. These aristocratic families supported the town's development; new manufacturing workshops and factories of German industrialists were established and the construction industry flourished. The chateau forest nursery became widely renowned. For example, the special variant of spruce bred in the forest nursery now forms vast forests in Canada. The Post Office started operating in the town as far back as in 1854, the first mutual savings bank in 1869, a sewage system and gradual water supply system were in operation by the end of the 19th century. In 1911, the town was connected to the electrical network.
In the 19th century, the families of factory owners Kühn and Tetzner started their business activities in the town. The town's importance grew as it was connected to the system of roads and railways (1872) providing easy access to other towns. Textile and paper products as well as Jirkov beer could be easily delivered to places near and far. The second half of the 19th century was characterised by the appearance of many educational and support organisations. First sporting, hiking as well as various different associations and clubs were established. In 1874, the first fireman fellowship was founded which (under a modified name - the Brigade of Voluntary Fireman) is active until the present time. The growth and prosperity was however disturbed by WWI which hit the town hard. The townspeople suffered a great deal.
In the 1920s, Jirkov became a district town for a short period of time. A short period of economic upturn occurred during which four textile factories prospered, three schools were active and 35 pubs offered their services. From the beginning of 1920s until the mid 1930s, the famous Kludský circus stayed in the town over the winters. WWII left Jirkov in relative peace. During the air raids of the allied forces aimed at the nearby Chomutov and the chemical factory, Jirkov was not even hit. The town was liberated on the 8th May 1945 by the Red Army.
The end of WWII brought abrupt discontinuation into the town's history. The expulsion of almost all the original German inhabitants which occurred shortly after the liberation represents the end of one long and important period of the town's historical development. The second period is the town's modern history; with the new inhabitants, new relations, connections, traditions etc. had to first be established, which are still influencing the present time. The social composition changed radically within a few months after the war. Several other settlement waves of new inhabitants from the Czech interior regions came in the following decades. New residential estates were being constructed almost continuously. 3500 Czechs and Moravians arrived in Jirkov from interior parts of the country immediately after WWII. The construction of a new residential estate therefore commenced as early as 1947. A second big wave of new inhabitants arrived around the end of the 1950s when the citizens of the town of Ervěnice, destroyed due to mining activities, arrived followed by families from other villages which followed the same destiny. More new inhabitants arrived in the 1980s and early 1990s attracted by the job opportunities offered by the many positions in the nearby mines and big factories.
The industrialisation started taking its toll in the1960s. The concentrations of harmful substances in the air often drastically exceeded the permitted limits in the following decades. The whole forest systems died on the slopes of the Ore Mountains. Moreover, the town was situated on the road 13 - the main transport route of the North-West. It is no wonder then that in 1958 the town ranked 3rd in the volume of traffic and negative effects of transport in the whole Czechoslovakia, preceded only by Prague and Ostrava. And the situation did not get better in the following years. Despite all these negative environmental effects, the water in Jirkov reservoir remained of such high quality that it was exported as bottled water suitable for infants to many places, Prague among them. From the mid 1980s, the environmental situation started improving slightly. This was due to the fact that the main road as well as rail line were relocated further away from the town. The worst smog calamity affected Jirkov in times when the new, democratically elected government of the Czech Republic had already started a program for improving the environmental conditions in the country. On the 8th February 1993, Jirkov was enveloped in greenish semi-darkness which remained all week. The highest concentrations of harmful substances were then measured in the air.
The democratic changes after the Velvet Revolution influenced all aspects of the town's life.
Most notably; the unemployment soared up as many factories situated in the town or in its surroundings were closed or scaled down. In the legal vacuum of that period, many people from the social margins with social adaptability problems started showing negative attitude to the town's assets and fellow citizens. The town council attempted to address this phenomenon and worked out a municipal ordinance which was passed by the municipal assembly on 3rd November 1992. This act got broad publicity and was dubbed the "Jirkov Ordinance". It however did not last long as it was subjected to examination by the General Public Prosecutor's Office and other authorities of the state judicial systems who condemned it. Therefore, it never became effective. Despite the fact that similar problems soon appeared in many other towns, this issue has not been legally addressed in the Czech Republic up to date.
Jirkov entered the new millennium as a largely modern town putting effort in developing its potential to become a popular tourist destination. Several important projects improving the town appearance were carried out - some of them funded from the town own budget, some of them to a large degree through public subsidies: The Jirkov Historical Cellars were saved and opened to public, the Kludsky Villa situated in Vinařická Street, where the world-famous circus family lived, was reconstructed, the château Červený hrádek is undergoing gradual reconstruction and it is being developed into a popular hotel and a place for wellness stays.
The town centre was reconstructed and so was the former Municipal House of Culture which was changed into a Climbing Arena. A majestic house situated in the town centre was reconstructed and the Municipal House of Culture moved into it. A multifunction sporting ground was constructed adjacent to the largest primary school in the town situated in Krušnohorská Street. All the buildings of Jirkov schools were gradually heat insulated and so were the blocks of flats in the residential estates. The public spaces in the residential estates were revitalised.
In 2002, Jirkov signed a Partnership Agreement with the town of Brand-Erbisdorf situated on the German side of the Ore Mountains, which opened possibilities for mutual visits and exchange programmes for pupils, sportsmen and sportswomen, fire brigades or elderly people. In 2013, Jirkov signed a similar Partnership Agreement with the Hungarian town of Bátonyterenye.