The Edo clan were a minor offshoot of the Taira clan, and first fortified the settlement known as Edo, which would later become Tokyo. The Imperial Palace now stands at this location.

During the Azuchi-Momoyama period, the clan was renamed the Kitami.

The clan originated in Chichibu in Musashi Province (now Saitama Prefecture). In the late 12th century, Edo Shigetsugu moved south and fortified the little hill at Edo, located where the Sumida River enters Tokyo Bay. This area is now the Honmaru and Ninomaru portions of Edo Castle.

Here, the Edo grew in military strength under the second patriarch, Edo Shigenaga.

In August 1180, Shigenaga attacked Muira Yoshizumi, an ally of the rival Minamoto clan. Three months later, he switched sides just as Minamoto Yoritomo entered Musashi. Shigenaga assisted the Minamoto in overthrowing the Taira in Kyoto. In return, Yoritomo granted Shigenaga seven new estates in Musashi Province, including Kitami in what is now Tokyo's western Setagaya Ward.

Records show that in 1457, Edo Shigeyasu surrendered his main base at Edo to Ota Dokan. Dokan was a vassal of the powerful Ōgigayatsu branch of the Uesugi clan under Uesugi Sadamasa. Sadamasa was the Kanto-Kanrei for the Ashikaga. Dokan built Edo castle on the site.

Edo (江戸, Edo^?, literally "bay-entrance" or "estuary"), also romanized as Yedo or Yeddo, is the former name of the Japanese capital Tokyo. It was seat of power for the Tokugawa shogunate, which ruled Japan from 1603 to 1868. During this period it grew to become one of the largest cities in the world and home to an urban culture centered on the notion of a "floating world".

From the establishment of the Tokugawa bakufu's headquarters at Edo, although Kyoto remained the formal capital of the country the de facto capital was now Edo; it was the center of political power. Edo grew from what had been a small, little-known fishing village in 1457 to a metropolis with an estimated population of 1,000,000 by 1721 (the largest city in the world at the time).

Edo was repeatedly devastated by fires, with the Great Fire of Meireki in 1657 (in which an estimated 100,000 people died) the most disastrous. During the Edo period there were about 100 fires (most begun by accident, often quickly escalating and spreading through neighbourhoods of wooden machiya which were heated with charcoal fires. Between 1600 and 1945, Edo/Tokyo was leveled every 25–50 years or so by fire, earthquakes, tsunami, volcanic eruptions or war.