Constructed in the Dravidian style of architecture, the temple is glorified in the Nalayira Divya Prabandham, the early medieval Tamil canon of the Alvar saints from the 6th–9th centuries CE.

Devanathaswamy is believed to have appeared to Adishesha (the serpent-mount of Vishnu), the sage Markandeya, and the Hindu god Indra.

Following the legend, the image of the presiding deity holds a lotus, the symbol of Brahma and has a third eye like Shiva, denoting the oneness.

According to the accounts, a group of sages wanted to view a theophany of Vishnu and went all the way to Tirupparkadal, the Ocean of Milk.

The guardians there stated that they could meet Vishnu only in a place close to the seashore north of Kumbakonam, south of Tirupathi and west of Kanchipuram.

They could view Mahavishnu in resplendent form with his weapons Sudarshana Chakra (discus), Panchajanya (conch) and Kaumodaki gracing his arms.

[1] As per another legend, Vishnu handed the job of obtaining the pure water of lake Vraja Tirtha located in the netherworld to Garuda, the eagle vahana.

The elongated transaction delayed the proceedings and Vishnu turned to his other prime devotee Adhishesha the serpent who constructed a well by whipping the earth with his tail.

In modern times, the temple is maintained and administered by the Hindu Religious and Endowment Board of the Government of Tamil Nadu.

The river Kedilam, located on the other side of the temple flows from south to north and is locally called Uttaravahini.

The sanctum also houses the image the consort, Senkamalavalli Thayar (also called Hemabhujavalli, Vaikunta Nayagi and Amruthavarshini) in sitting posture.

The festival images of Vishnu, called by different names like Moovaraghia oruvan, Achuta, Dvistantha, Devanatha, Vibhuthanatha and Dasyatha, is housed in the sanctum.

There is a separate shrine housing Rama, though the presiding deity is Devanathaswamy, the temple is known for Hayagriva, the horse faced avatar of Vishnu.

[1] The temple priests perform the pooja (rituals) as per Vadakalai sampradayam during festivals and on a daily basis (Vaikashasana Agama).

The temple rituals are performed six times a day: Ushatkalam at 7 a.m., Kalashanti at 8:00 a.m., Uchikalam at 12:00 p.m., Sayarakshai at 6:00 p.m., Irandamkalam at 7:00 p.m. and Ardha Jamam at 10:00 p.m. Each ritual has three steps: alankaram (decoration), naivedyam (food offering) and deepa aradhanai (waving of lamps) for both Neelamegha Perumal and Tirukannapura Nayagi.

The temple is revered in Nalayira Divya Prabandham, the 7th–9th century Vaishnava canon, by Thirumangai Alvar in eleven hymns.

Divya Kavi Pillai Perumal Aiyangar in his Ashta Prabanda states that heavens shower flowers on the devotees of the temple.

Indra performed Vaishnava Yagna at this place to worship Vishnu to win over the demon king Vritasura.