The Hirata school descends from Hirata Dōnin (平田道仁), the craftsman who expressed the sumptuous, luxurious beauty of -period art in sword fittings through the technique of shippō (七宝, cloisonné enamel). Commonly known as Hikoshirō, Dōnin was a native of Kyoto, and his skills are traditionally said to have been learned from Korea. Cloisonné of that time accorded with contemporary taste and was employed for architectural metal fittings at sites such as Fushimi Castle and the Jurakudai, attracting great attention as a fresh form of decorative craft. Around the Keichō era (1596–1615) Dōnin entered the service of Tokugawa Ieyasu; he moved from Sunpu to , and thereafter the Hirata family — distinct from the Hirata line — served generation after generation as official retained artisans (kakae-kō) of the Tokugawa shogunate, granted a residence in and a stipend of ten persons' rations. His eldest son and successor, the second-generation Shūichi (就一), had an audience with Tokugawa Iemitsu in Shōhō 3 (1646) and was maintained as a bakufu craftsman specializing in mounting ornaments.
The school's defining art is cloisonné applied to sword fittings, above all gold-wire cloisonné inlay (-sen shippō zōgan) and the distinctive Hirata manner of flush enamel inlay (shippō suemon-zōgan), set against grounds of polished or stone-textured , iron, and brass. Mount was the subject at which the first and second generations most excelled — the summit crowned in pure-white enamel snow, the long foothills shimmering in pale blue, with gold inlay for rocks symbolizing wealth — alongside lotus blossoms on the water, willows with small birds, snow-capped mountain ranges, rain dragons (uryū), and floral arabesques. The palette centers on a richly opalescent, milky-toned enamel inherited from Dōnin, joined by emerald-like transparent green and fresh hues of vermilion, yellow, and blue. Even without enamel, the family's meticulous gold-wire inlay alone renders intricate tōka arabesque and scattered-motif designs that embody "the technique and high dignity of the Hirata main line." Successive heirs used Hikoshirō as their common name, and signed works from the first through the fourth generations are exceedingly few. From around the fifth-generation Jūmon (就門), a small number of works without cloisonné appear; the eighth-generation Harunari (春就), unlike other heads of the house, also studied chōkin (metal carving) under the Yasuda family, likewise shogunal purveyors, producing yōbori and work on , a manner transmitted in turn to the ninth-generation (就将).
The cloisonné techniques were guarded as an isshi sōden — a secret, single-heir transmission — down into the Meiji era, when the family applied its hereditary art to the manufacture of the decorations and orders of the Japanese state, beginning with the Order of the Golden Kite ( Kunshō). Patronage remained at the highest level throughout: the tenth-generation Hikoshirō Haruyuki (春行) fulfilled a shogunal commission ordered in Genji 1 (1864) and completed in Keiō 1 (1865) that was transmitted within the Tokugawa house; a ceremonial mounting with fittings by Harunari passed down as an heirloom of the Kishū Tokugawa family; and worked on commission from the Lord of Nagashima. The school's influence extended beyond the main line — Nakamura Haruhiro, retained craftsman of the Daishōji Maeda house, became a pupil of Harunari and was permitted to use the Hirata surname. Dōnin's -period masterpieces, with their antique elegance and dignified restraint, are esteemed as revealing "the very essence of Japanese cloisonné art," and celebrated examples were treasured in collections such as that of Ryūshidō, Mitsumura Toshimo — securing the Hirata line's place as the fountainhead of cloisonné in the tosogu canon.