William Lyon Mackenzie
The township of York, which until 1793 had been known as "Toronto", incorporated as a city (meaning it received local self-government) on March 6, 1834, taking the name of "the City of Toronto" to distinguish it from New York City and the dozen other settlements named 'York' in Upper Canada. The Tories and the Reformers fielded candidates for Toronto's first municipal election, held on March 27, 1834, with the Reformers winning a majority on the Toronto City Council. Mackenzie was elected as an alderman. The City Council then met to decide who should become mayor. Mackenzie, after being nominated by Franklin Jackes, defeated John Rolph in the vote and thereby became the first Mayor of Toronto.
George Gurnett
When York was incorporated in May 1834 as the city of Toronto, Gurnett was elected to the city council as the representative for St. George's Ward. During his 17 years on the city council he served as mayor four times, in 1837, 1848, 1849, and 1850. Due to his long service on council and his years as mayor he is often considered to be one of the founders of the city of Toronto.