Even though Valeč first appears in written records in 1358, first settlements must have existed much earlier due to its favourable location at the foot of the south-western part of Doupovské hory (Doupov Mountains). The current name originates in the first half of the 13th century and it is derived from the name Válek (possibly a modified form of Valentin) who owned the local manor.
A milestone in the history of the village is the privilege awarded to it on December 2, 1514 by King Vladislav Jagelonský (also denoted as Ladislaus Jagiellon) upon the request of the owner of the Valeč estate, Jakub of Vřesovice. The king raised Valeč to the status of a township enjoying such rights as the right to hold weekly markets, annual 9-day markets, or the right to use a seal with green wax. In 1517, the Valeč estate was acquired by Kryštof Štampach whose family influenced the development of the township for two centuries, like their successors, the Counts of Globen, who held the estate since 1721.
The small town of Valeč is dominated by a chateau built on the site of a Gothic castle and reconstructed in Renaissance style. When in possession of Count Jan Kryštof Kager of Štampach, the chateau was partially rebuilt in Baroque style according to the design of builder F. Barelli and subsequently by G. A. Biana Rosso and its grand-scale Baroque reconstruction was completed by the Globen family in the years 1730 and 1733. Some minor Neo-Baroque renovations were carried out in 1895 and 1896. On April 2, 1976, the chateau was severely devastated by a fire, the consequences of which have not been remedied to this day due to insufficient funds.
An integral part of the chateau is its renowned vast park, which was founded and modified in two phases just as the chateau. During the second phase, the park received its well-known gallery of statues by Matyáš Bernard Braun, of which 27 have been preserved. Valeč thus owns the second largest set of statue copies of the renowned artist after Špork's Kuks Chateau in eastern Bohemia.
A sight of major historical value in Valeč is also the chateau Church of the Holy Trinity built by architect G. A. Biana Rosso in the course of years from 1710 and 1728, and the Column of the Holy Trinity in front of the church, which was created by F. M. Kaňka in 1725 and decorated with statues of the patrons of Bohemia by M. B. Braun. The small town also offers other historical monuments worth visiting, such as the parish building or the town Church of St. John the Baptist.