He was born outside the gates of Sāvatthi in a fishing village, where his father was the headman of five hundred families. When he came of age, he was fishing one day in the Aciravatī, and, casting his net, caught a large golden colour fish. Yasoja and his companions took the fish to Pasenadi who sent them to the Buddha. The Buddha told them that the fish had been a wicked monk in the time of Kassapa Buddha, and had since suffered in purgatory, where his mother and sisters still were. He then preached to them the Kapila Sutta, and Yasoja and his companions, greatly moved, renounced the world (ThagA.i.356f.).
The Udāna mentions (Ud.iii.3) how, later, Yasoja and five hundred of his companions went to see the Buddha at Jetavana. There they stood talking to the monks who lived there and made a great uproar. The Buddha, sending Ananda to fetch them, asked them to remove themselves from his presence, as they were behaving like fishermen. Taking his admonition to heart, they returned to the banks of the Vaggumudā in the Vajji country, and there they determined to lead such lives as would commend them to the Buddha. During the rainy season, they all put forth effort and attained arahantship. Some time after, the Buddha visited Vesāli during a journey and asked Amanda to send for Yasoja and his friends as he desired to see them. Ananda sent a message. When the monks arrived, they found the Buddha lost in meditation, and they, too, seated themselves and entered into samādhi, remaining thus throughout the night. Amanda could not understand why the Buddha, having sent for Yasoja and his companions, should have sunk into samādhi without greeting them, and three times during the night he tried to remind the Buddha of their arrival; but the Buddha ignored his warnings and in the morning explained to him that it was more joy for them all to live in the bliss of samādhi than to indulge in mere conversation. It is said in UdA.185 that the Buddha spent the night in samādhi in order to show Yasoja and his companions that he regarded them as equals.
It is said (ThagA.i.357) that when Yasoja and the others visited the Buddha at Vesāli, they were very thin and had grown uncomely through their austerities. The Buddha commended their self denial in a verse, and Yasoja, appreciating the Buddha's praise, uttered two other verses, exalting the love of solitude (Thag.243 5).
In the time of Vipassī Buddha Yasoja belonged to a family of park-keepers (ārāmagopakā), and one day seeing the Buddha travel through the air, he gave him a labuja fruit (ThagA.i.356). In the time of Kassapa Buddha, Yasoja was the leader of a band of five hundred robbers. They were pursued by the villagers and fled into the forest for safety. There they saw a monk sitting on a stone and asked him for protection. He advised them to take the five precepts, and when they had done so, he exhorted them never to violate these precepts even if keeping them meant the loss of their lives. Soon after, they were captured and killed. But remembering the monk's admonition at the moment of death, they harboured no hatred against anyone, and after death were reborn in the deva world (UdA.179f).
The Vinaya relates (Vin.i.239) how once, when Yasoja was ill, drugs were brought for his use, but as the Buddha had forbidden the use of a special place for storing such things (kappiyabhūmi) they were left out of doors and were partly eaten by vermin, the remainder being carried away by robbers. When the matter was reported to the Buddha, he allowed the use of a duly chosen kappiyabhūmi. The Apadāna verses ascribed to Yasoja in the Theragāthā are, in the Apadāna itself, found in two places: one under Labujadāyaka (Ap.ii.409) and the other, with slight variations, under Labujaphaladāyaka. Ap.i.295.