The temple is one of Vaishnavism's 108 principal Divya Desams, and is glorified in the Prabandha Divya. This shrine is glorified by the Divya Prabandha as one of the 13 Divya Desams in Malai Nadu (corresponding to Kerala with Kanyakumari District today). Tamil poet Alvar Nammalvar, of the 8th century, sang Padmanabha's glories. The Ananthapuram temple in Kasaragod is thought to be Padmanabhaswamy 's original seat.
Parasurama is believed to have consecrated Sree Padmanabha's idole in Dwapara Yuga. Parasurama assigned seven Potti families to 'Kshethra karyam' (Temple Administration) – Koopakkara Potti, Vanchiyoor Athiyara Potti, Kollur Athiyara Potti, Muttavila Potti, Karuva Potti, Neythasseri Potti, and Sreekaryathu Potti. Parasurama instructed King Adithya Vikrama of Vanchi (Venad) to do 'Paripalanam' (Protection) of the Temple. Parasurama gave Tharananallur Namboothiripad the Templar Tantram. In 'Kerala Mahathmyam' which forms part of 'Brahmanda Puranam' this legend is recounted in detail.
Another version relating to the consecration of the Temple 's Main Idol concerns the legendary sage Vilvamangalathu Swamiyar. Swamiyar, who lived in the Kasaragod district near Ananthapuram Temple, prayed to Lord Vishnu for his darshan or "auspicious sight" It's believed that the Lord came in the form of a little mischievous boy. The boy defiled the idol that was being held for Puja. The sage was furious at this and chased away the boy who had vanished before him. The sage wept for forgiveness and pleaded for another darshan as a sign to know the boy was no ordinary mortal.He heard a voice saying, "If you want me to come to the Anathavana (the infinite forest or ananthakadu), after a long hunt, walking on the banks of the Laccadive River, a pulaya lady told her child that she would throw him to Ananthankadu. He was pleased at the moment when the Swami heard the word Ananthankadu.He continued to Ananthankadu based on the lady's directions which he inquired about. Searching for the child, the Sage reached Ananthankadu. There he saw the boy merging into a tree called Iluppa (Indian Butter Tree). The tree sunk down and became Anantha Sayana Moorti (Vishnu reclining on the Anantha celestial snake).But the edifice assumed by the Lord was of an extraordinarily large size, with His head at Thiruvattar near Thuckalay Tamil Nadu, Body or Udal at Thiruvananthapuram, and Lotus-feet at Thrippadapuram near Kulathoor and Technopark (Thrippappur), making it some eight miles. The Sage begged the Lord to shorten the length of his staff to a smaller proportion that would be three times that. The Lord immediately shrank to the form of the Idol which is currently seen in the Temple. Yet even then several trees in Iluppa obstructed the Lord 's full dream. Three pieces of the Sage saw the Lord-thirumukham, thiruvudal, and thrippadam.Swami prayed forgiveness to Padmanabha. The Swami offered to the Perumal Rice Kanji and Uppumanga (salted pieces of mango) in a coconut shell that he received from the pulaya woman. Koopakkara Potti and Karuva Potti belonged to the place where the Sage had lord darsan. A Temple was built with the aid of the ruling King and some Brahmin households. The Temple of Ananthankadu Nagaraja still exists northwest of the Temple of Padmanabhaswamy. The Swamiyar Samadhi (final resting place) exists to the west of the Temple of Padmanabha. A Temple of Krishna was built above the Samadhi. This Temple, known as Sri Krishna Swami Temple of Vilvamangalam, belongs to Naduvil Madhom.