The Annex was subdivided in the 1870's and 1880's, and was immediately one of Toronto's elite neighbourhoods. The Annex's first residents included the likes of Timothy Eaton, the patriarch of Eaton's department store, and George Gooderham, president of the Gooderham and Worts Distillery. The Annex's Golden Era lasted until the 1920's, when the upper classes began to migrate northward to newer and more fashionable suburbs in Forest Hill and Lawrence Park. Those who stayed behind helped form the Annex Residents Association. This powerful lobby group saved the Annex from the proposed Spadina Expressway which would have divided the Annex in half, had it been built. The Annex has endured and is now over one hundred years old. It remains one of Toronto's premier neighbourhoods.

The Annex is Toronto's most heterogeneous community. Its residents include successful business people, prominent artists, University of Toronto students and faculty, and people from all walks of life. This vibrant neighbourhood draws its energy from the University of Toronto campus, as well as from the bars, restaurants and nightclubs that crowd together along Bloor Street.

Many of the rooming houses and multi-unit homes in the Annex have recently been converted back to single family houses reflecting the return to prominence of this historic Toronto neighbourhood.