ruler of a large empire in northern India from 606 to 647. He was a Buddhist convert in a Hindu era. His reign seemed to mark a transition from the ancient to the medieval period, when decentralized regional empires continually struggled for hegemony.

The second son of Prabhākaravardhana, king of Sthāṇvīśvara (Thānesar, in the eastern Punjab), Harṣa was crowned at age 16 after the assassination of his elder brother, Rājyavardhana, and an encouraging “communication” with a statue of the Buddhist Avalokiteśvara bodhisattva. He soon made an alliance with King Bhāskaravarman of Kāmarūpa and warred against King Śaśāṅka of Gauḍa, his brother's assassin. At first he did not assume the title of king but merely acted as a regent; after making his position secure, however, he declared himself sovereign ruler of Kannauj (in Uttar Pradesh) and formally transferred his capital to that city. Though never defeating Śaśāṅka, his large army waged incessant warfare for six years, conquering the “five Indies,” thought to be Valabhī, Magadha, Kashmir, Gujarāt, and Sind. His influence extended from Gujarāt to Assam, but the area directly under his control probably comprised no more than the modern Uttar Pradesh, with parts of Punjab and Rājasthān. He attempted to conquer the Deccan (c. 620) but was driven back to the Narmada River by the Cālukya emperor Pulakeśin II. Bringing most of the north under his hegemony, Harṣa apparently made no attempt at building a centralized empire but ruled according to the traditional pattern, leaving conquered kings on their thrones and contenting himself with tribute and homage.

Harṣa is known mainly through the works of Bāṇa, whose Harṣacarita (“Deeds of Harṣa”) describes Harṣa's early career, and of the Chinese pilgrim Hsüan-tsang (Xuanzang), who became a personal friend of the king, though his opinions are questionable because of his strong Buddhist ties with Harṣa. Hsüan-tsang depicts the emperor as a convinced Mahāyāna Buddhist, though in the earlier part of his reign Harṣa appears to have supported orthodox Hinduism. He is described as a model ruler—benevolent, energetic, and just, and active in the administration and prosperity of his empire. In 641 he sent an envoy to the Chinese emperor and established the first diplomatic relations between India and China. He established benevolent institutions for the benefit of travelers, the poor, and the sick throughout his empire. He held quinquennial assemblies at the confluence of the Ganges and the Yamuna rivers at Prayāg (Allahābād), at which he distributed treasures he had accumulated during the previous four years. A patron of men of learning, Harṣa sponsored the chronicler Bāna and Mayūra, a lyric poet. Himself a poet, Harṣa composed three Sanskrit works: Nāgānanda, Ratnāvalī, and Priyadarśikā.

A period of anarchy, or at least a splintering of his empire, followed Harṣa's death, with the later Guptas ruling over a portion of it.