Despite basic reliance on this sutra for doctrinal views, much of the technical terminology that comes to define the school is not found in the sutra itself, but in the commentarial works of its early founders. The founding of the school is traditionally attributed to a series of five 'patriarchs' who were instrumental in developing its doctrines. These five are: Dushun 杜順, Zhiyan 智儼, Fazang 法藏, Chengguan 澄觀 and Zongmi 宗密. Another important figure in the development and popularization of Huayan thought was the lay scholar Li Tongxuan 李通玄. Some accounts of the school also like to extend its patriarchship earlier to Aśvaghoṣa 馬鳴 and Nāgârjuna 龍樹. Although there are certain aspects of this patriarchal scheme that are clearly contrived, it is fairly well accepted that these men each played a significant and distinct role in the development of the school: for example, Dushun is known to have been responsible for the establishment of Huayan studies as a distinct field; Zhiyan is considered to have established the basic doctrines of the sect; Fazang is considered to have rationalized the doctrine for greater acceptance by society; Chengguan and Zongmi are understood to have further developed and transformed the teachings. After the time of Zongmi and Li Tongxuan the Chinese school of Huayan generally stagnated in terms of new development, and then eventually began to decline. The school, which had been dependent upon the support it received from the government, suffered severely during the purge of 841–5, never to recover its former strength. Nonetheless, its profound metaphysics, such as that of the four dharmadhātu 四法界 of interpenetration based on the pair of principle and phenomena 理事, had a deep impact on surviving East Asian schools, especially the Chan school. Huayan also had a deep influence on the thought of the Neo-Confucian tradition that arose in the Song period, seen in the basic Neo-Confucian li-qi 理氣 paradigm, and in oft-repeated slogans such as "the humane man forms a single body with the universe." The extent of this influence is so great that one can see citations in scholarly works that are attributed as being of Huayan origin, but are actually from Neo-Confucian texts.

A pronounced and enduring impact of the Huayan school was to be seen in Korea, where it was transmitted by the monk Uisang 義湘, who had been, along with Fazang, a student of Zhiyan. After Uisang returned to Korea in 671, he worked vigorously toward the establishment of the Hwaeom school on the peninsula. The Hwaeom school became strongly established under the influence of a long series of erudite and prolific masters, most prominent of whom is Gyunyeo 均如 (923–973). The Hwaeom school remained in the position of predominant doctrinal school in Korea up till the end of the Goryeo period, when it was placed into a forced merger with the Seon school 禪宗. Within the Seon school, Hwaeom thought held a deep influence, as seen in the writings of monks such as Jinul 知訥 (1158–1210). It continues to exercise a powerful influence within Korean Seon up to the present.

Huayan studies were founded in Japan when, in 736, the scholar-priest Rōben 良辯 (originally a Hossō 法相 specialist) invited the Korean Simsang 審祥 to give lectures on the Huayan jing at Konshuji 金鐘寺. When the construction of Tōdaiji 東大寺 was completed, Rōben entered that temple to formally initiate Kegon as a field of study in Japanese Buddhism, and the Kegon Shū would become known as one of the 'six Nara 奈良 schools.' Kegon thought was later be popularized in Japan by Myōe 明惠, who combined its doctrines with those of the esoteric school 密教, and Gyōnen 凝然, who is most responsible for the establishment of the Tōdaiji lineage of Kegon.

The most important philosophical contributions of the Huayan school were in the area of its metaphysics, as it taught the doctrine of the mutual containment and interpenetration of all phenomena 事事無礙: that one thing contains all things in existence, and that all things contain one. The school is also the origin of the notion of 法性 Dharma-nature, by which name it was also called.