The temple is dedicated to the bodhisattva Kannon (Avalokitesvara). According to legend, a statue of the Kannon was found in the Sumida River in 628 by two fishermen, the brothers Hinokuma Hamanari and Hinokuma Takenari. The chief of their village, Hajino Nakamoto, recognized the sanctity of the statue and enshrined it by remodeling his own house into a small temple in Asakusa, so that the villagers could worship the Kannon.
The first temple was founded in 645 C.E., which makes it the oldest temple in Tokyo. In the early years of the Tokugawa shogunate, Tokugawa Ieyasu designated Sensō-ji as tutelary temple of the Tokugawa clan.
The Nishinomiya Inari Shrine is located within the precincts of Sensō-ji; and a torii identifies the entry into the hallowed ground of a Shinto shrine. A bronze plaque on the gateway structure lists those who contributed to the construction of the torii, which was erected in 1727 (Kyōhō 12, 11th month).
During World War II, the temple was bombed and destroyed. It was rebuilt later and is a symbol of rebirth and peace to the Japanese people. In the courtyard there is a tree that was hit by a bomb in the air raids, and it had regrown in the husk of the old tree and is a similar symbol to the temple itself.