He was the son of a very wealthy brahmin family of Donavatthu near Kapilavatthu and was born before the Buddha. He came to be called by his family name Konda˝˝a. He was learned in the three Vedas, excelling in the science of physiognomy.
When the Buddha was born he was among the eight brahmins (the others being Rāma, Dhaja, Lakkhana, Mantī, Bhoja, Suyāma and Sudatta. In the Milinda (236), where the eight names are given, Konda˝˝a appears as Ya˝˝a) sent for to prognosticate, and though he was yet quite a novice he declared definitely that the babe would be a Buddha. Thereafter he lived awaiting the Bodhisatta's renunciation. After this happened he left the world with four others, and the five later became known as the Pa˝cavaggiyā (J.i.65f.; AA.i.78-84; ThagA.ii.1ff). When, after the Enlightenment, the Buddha visited them at Isipatana and preached the Dhammacakkappavattana Sutta, Konda˝˝a and eighteen crores of brahmas won the Fruit of the First Path. As he was the first among humans to realise the Dhamma the Buddha praised him saying "a˝˝āsi vata bho Konda˝˝o" twice; hence he came to be known as A˝˝ata Konda˝˝a. (Vin.i.12; UdA.324, 371; Mtu.iii.333).
It is interesting to note that in the Burmese MSS. the name appears as A˝˝āsi-Konda˝˝a. The Cy. explains A˝˝āta-Konda˝˝a by "pativedha Konda˝˝a." In the ThagA. he is called A˝˝a-Konda˝˝a. Mrs. Rhys Davids suggests that A˝˝ā was his personal name (Gotama the Man, p.102).
Five days later when the Anattalakhana Sutta was preached he became arahant (Vin.i.13-14). He was the first to be ordained with the formula "ehi, bhikkhu" and the first to receive higher ordination. Later, at Jetavana, amidst a large concourse of monks, the Buddha declared him to be the best of those who first comprehended the Dhamma (AA.i.84). He was also declared to be pre-eminent among disciples of long-standing (ratta˝˝ūnam) (A.i.23).
In the assembly of monks he sat behind the two chief disciples. Finding that his presence near the Buddha was becoming inconvenient to himself and others (For his reasons see AA.i.84; SA.i.216), he obtained the Buddha's permission to go and live on the banks of the Mandākini in the Chaddanta-vana, where he stayed for twelve years, only returning at the end of that period to obtain the Buddha's leave for his parinibbāna. The elephants in the forest took it in turns to bring him his food and to look after him. Having bidden farewell to the Buddha, he returned to Chaddanta-vana, where he passed away (SA.i.218; AA.i.84). We are told (SA.i.219) that all Himavā wept at his death. The obsequies were elaborately performed by eight thousand elephants with the deva Nāgadatta at their head. All the devas from the lowest to the highest brahma world took part in the ceremony, each deva contributing a piece of sandalwood. Five hundred monks, led by Anuruddha, were present. The relics were taken to Veluvana and handed over to the Buddha, who with his own hand deposited them in a silver cetiya which appeared from the earth. Buddhaghosa states that the cetiya existed even in his time (SA.i.219).
Several verses attributed to Konda˝˝a are given in the Theragāthā, admonishing fellow celibates to lead the higher life, because everything is impermanent, bound to ill and void of soul (Thag.674-88).
On one occasion he preached to Sakka at the latter's own request; Sakka expressed himself as greatly pleased because the sermon was worthy even of the Buddha."
Vangisa once extolled his virtues in the presence of the Buddha (Thag.v.673; ThagA.ii.3).
In Padumuttara's time Konda˝˝a had been a rich householder, and, seeing one of the monks given preference in seniority, he wished for a similar rank for himself in the future. Towards this end he did many acts of piety, one of them being to build a golden chamber over the Buddha's relics. In Vipassī's time was a householder, Mahākāla, and gave to the Buddha the first-fruits of his field in nine stages of their produce (ThagA.ii.1; DhA.i.80).
According to the Apadāna (i.48f.; The Divy 430 mentions another previous birth of Konda˝˝a), he offered the first meal to Padumuttara after his Enlightenment.
Punna Mantānīputta was his nephew and was ordained by him. ThagA.i.37.
Mantānī was A˝˝āta-Konda˝˝a's sister.