Hikone Castle was the residence of the Ii family, feudal lords who held important positions in the Edo shogunate and supported the reign of the Tokugawa family. In 1604, by order of Tokugawa Ieyasu, construction of the castle began in an effort to supersede Sawayama Castle, which had previously served as a base for the Hikone area. Hikone Castle was completed around 1622. Along with Himeji Castle in Hyogo Prefecture, which is registered as a World Heritage Site, Hikone Castle is one of only five castles in Japan that has a keep designated as a national treasure.

The Hikone area has been a strategic location since ancient times due to its location at the crossroads of Tosendo Road (Nakasendo Road in the Edo Period) and Hokuriku Road (Hokkoku Road in the Edo Period). Up until the Warring States Period, Sawayama Castle served as the base castle, but in the Edo Period, construction of Hikone Castle began under the order of Tokugawa Ieyasu (1533–1616) as a strategy to wipe out Sawayama Castle. The construction of Hikone Castle was initially led by the Shogunate, and by 1607, the main parts of the castle were built in anticipation of warfare. After the Osaka Summer Campaign in 1615, the Ii family took the lead in building the Omote Goten ("front castle,") and developing the castle town, creating a city for samurai and townspeople alike. Hikone Castle also housed the largest stockpile of rice for the Tokugawa military forces, and the Ii family's troops served to fend off the surrounding area and the forces in the western part of the region.

Hikone Castle, now a symbol of Hikone City and beloved by many, was once on the brink of demolition during the Meiji Era (1868-1912). Amid this time of rapid modernization, castles around Japan began to be dismantled, and Hikone Castle was also scheduled for demolition. However, in 1878 (Meiji 11), when Emperor Meiji passed through Hikone on his way back from a tour of the Hokuriku region, he ordered the preservation of Hikone Castle; thus sparing it from demolition. There are various theories as to why the Emperor gave the order, including that Okuma Shigenobu (1838-1922), who was part of the Emperor's entourage, was saddened at the thought of Hikone Castle being lost, or that Kaneko, the Emperor's cousin and wife of the temple keeper of Fukuda Temple in Nagasawa, Omi-machi, where the Emperor stopped for respite, petitioned for Hikone Castle's preservation.

In 1952, Hikone Castle's keep, annexed turrets (Tsuke Yagura), and multi-story gate turrets (Tamon Tagura) were all designated national treasures. The main keep, which consists of three stories and a triple-layer roof, has a beautiful and varied appearance with an emphasis on the exterior. It is said to have been relocated from Otsu Castle, and not only is it magnificent to behold, but it also excels in its original function as a military strongpoint. In addition to the three national treasures of the keep, the annexed turrets, and the multi-story gate turrets, there are many other buildings of high historical value that have been designated as important cultural properties, such as the Nishinomaru three-storey turret, which once played a crucial part as the key to defense against enemy attacks from the west, Drum Gate Turret (Taiko-mon Yagura) and Tsuzuki-Yagura (linking turrets) that ominously guards the main entrance to the castle, and the Tenbin turret, an important post that prevented enemies from penetrating the honmaru (main castle.) Genkyu Rakurakuen Garden that girths the castle is a traditional Japanese garden designated as a national place of scenic beauty.