He was the son of a Paribbājaka and entered the Order after seeing the Buddha perform the Twin Miracle; he later attained arahantship through jhāna. There was a Paribbājaka, named Kātiyāna, whom he had known as a layman, and Kātiyāna, having become destitute after the Buddha's appearance in the world, asked Sāmaññakāni what he could do to get happiness in this world and the next. His friend answered that he should follow the Noble Eightfold Path (Thag.vs.35; ThagA.i.98f). We are told (ThagA.i.450) that Kātiyāna later joined the Order and became an arahant.
Sāmaññakāni is evidently identical with Mañcadāyaka (Pecchadāyaka) of the Apadāna (Ap.i.455). Ninety one kappas ago he gave a bed to Vipassī Buddha. Perhaps he is also identical with Sāmandakāni (q.v.).