Thanks to negotiations led by Francis Day with ruler of Chandragiri in 1639, English succeeded in purchasing a piece of coastal land, originally called Chennirayarpattinam or Channapatnam, where the Company began the construction of a harbour and a fort.

The fort was completed on 23 April 1644 at a cost of £3,000,[5] coinciding with St. George's Day, celebrated in honour of the patron saint of England.

It also helped to establish English influence over the Carnatic region and to keep the kings of Arcot and Srirangapatna, as well as the French forces based at Pondicherry, at bay.

In 1665, after the EIC received word of the formation of the new French East India Company, the fort was strengthened and enlarged while its garrison was increased.

[6] According to the 17th-century merchant and traveller Thomas Bowrey, Fort St. George was: without all dispute a beneficial place to the Honourable English India Company, and with all the Residence of theire Honourable Agent and Governour all of their Affaires Upon this Coast and the Coast of Gingalee, the Kingdoms also of Orixa, (Orissa) Bengala (Bengal), and Pattana (Patna), the said Governour and his Councell here resideigne, for the Honour of our English Nation keepinge and maintainneinge the place in great Splendour, Civil and good Government, Entertaineinge nobly all Foraign Embassadors, and provideinge great quantities of Muzlinge (Muslin) Callicoes (Calico) &c. to be yearly transported to England.

It briefly passed into the possession of the French from 1746 to 1749, but was restored to Great Britain under the Treaty of Aix-la-Chapelle, which ended the War of the Austrian Succession.

The Fort now serves as one of the administrative headquarters for the legislative assembly of Tamil Nadu state and it still houses a garrison of troops in transit to various locations at South India and the Andamans.

The Fort Museum, which is the only ticketed institution of the Archaeological Survey of India in the complex,[12] exhibits many items of the period of English and later British rule.

The objects on display in the museum are the weapons, coins, medals, uniforms and other artefacts from England, Scotland, France and India dating back to the colonial period.

In 2010 the legislature and the secretariat moved to a new location and the old assembly complex was converted into a library for the Central Institute of Classical Tamil.

[17] An arch commemorating the diamond jubilee of Tamil Nadu Legislative Assembly is under construction near the Fort on Rajaji Salai close to Napier Bridge.

The legend 'Tamil Nadu Legislative Assembly diamond jubilee commemorative arch' would be inscribed in English and Tamil, in addition to the words '60 years'.

Earlier, the arch was planned to be constructed close to the entrance of Fort St. George, but was later relocated beyond the prohibitive zone, as per AMASR Act.