Ramanuja was born to Tamil parents in the village of Sriperumbudur, Tamil Nadu. His followers in the Vaishnava tradition wrote hagiographies, some of which were composed in centuries after his death, and which the tradition believes to be true.
The traditional hagiographies of Ramanuja state he was born to mother Kānthimathi and father Asuri Kesava Somayāji, in Sriperumbudur, near modern Chennai, Tamil Nādu. He is believed to have been born in the month of Chaitra under the star Tiruvadhirai. They place his life in the period of 1017–1137 CE, yielding a lifespan of 120 years. These dates have been questioned by modern scholarship, based on temple records and regional literature of 11th- and 12th-century outside the Sri Vaishnava tradition, and modern era scholars suggest that Ramanuja may have lived between 1077-1157 CE.
Ramanuja married, moved to Kānchipuram, studied in an Advaita Vedānta monastery with Yādava Prakāśa as his guru. Ramanuja and his guru frequently disagreed in interpreting Vedic texts, particularly the Upanishads. Ramanuja and Yādava Prakāśa separated, and thereafter Ramanuja continued his studies on his own.
He attempted to meet another famed Vedanta scholar of 11th-century Yamunāchārya, but Sri Vaishnava tradition holds that the latter died before the meeting and they never met. Ramanuja was the great-grandson of Yamunāchārya through a grand-daughter. However, some hagiographies assert that the corpse of Yamunāchārya miraculously rose and named Ramanuja as the new leader of Sri Vaishnava sect previously led by Yamunāchārya. One hagiography states that after leaving Yādava Prakāśa, Ramanuja was initiated into Sri Vaishnavism by Periya Nambi, also called Māhapurna, another Vedānta scholar. Ramanuja renounced his married life, and became a Hindu monk. However, states Katherine Young, the historical evidence on whether Ramanuja led a married life or he did renounce and became a monk is uncertain.
Ramanuja became a priest at the Varadharāja Perumal temple (Vishnu) at Kānchipuram, where he began to teach that moksha (liberation and release from samsara) is to be achieved not with metaphysical, nirguna Brahman but with the help of personal god and saguna Vishnu. Ramanuja has long enjoyed foremost authority in the Sri Vaishnava tradition.
A number of traditional biographies of Ramanuja are known, some written in 12th century, but some written centuries later such as the 17th or 18th century, particularly after the split of the Śrīvaiṣṇava community into the Vadakalais and Teṉkalais, where each community created its own version of Ramanuja's hagiography. The Muvāyirappaṭi Guruparamparāprabhāva by Brahmatantra Svatantra Jīyar represents the earliest Vadakalai biography, and reflects the Vadakalai view of the succession following Ramanuja. Ārāyirappaṭi Guruparamparāprabhāva, on the other hand, represents the Tenkalai biography. Other late biographies include the Yatirajavaibhavam by Andhrapurna.
Modern scholarship has questioned the reliability of these hagiographies. Scholars question their reliability because of claims which are impossible to verify, or whose historical basis is difficult to trace with claims such as Ramanuja learned the Vedas when he was an eight-day-old baby, he communicated with God as an adult, that he won philosophical debates with Buddhists, Advaitins and others because of supernatural means such as turning himself into "his divine self Sesha" to defeat the Buddhists, or God appearing in his dream when he prayed for arguments to answer Advaita scholars. According to J. A. B. van Buitenen, the hagiographies are "legendary biographies about him, in which a pious imagination has embroidered historical details".