The man after whom Georgetown is named, George Kennedy, was one of a group of settlers who came to Esquesing Township from the Niagara region. George's father, like others in that neighbourhood, had come from the United States and George, along with several brothers, had participated in the War of 1812. George's legacy of a stint in the Artillery was partial blindness in both eyes.

After the war, older brother Charles Kennedy was hired to survey part of one of the new townships the government had purchased from the Indians. In the process identified some of the best land and shortly before the survey was completed in the fall of 1819, five Kennedy brothers claimed land in the neighbourhood of Georgetown: George, Morris, Charles, Samuel and John. A few years later, their brother-in-law, Benajah Williams came to settle in the area now known as Glen Williams.

As the community grew up around the Kennedy settlement, George expanded his activities to include not just farming but milling, using power provided by Silver Creek, a tributary of the Credit River. He is reputed to have one of the first grist mills in the area and in the 1840s was complimented for some prize winning wool processing at his local factory

When Georgetown was booming in the 1850s George had much of his land surveyed into town lots and named the streets after his children. He died in 1870 having seen the community grow from a wilderness into a thriving centre of farming, industry and commerce.

The Kennedy family would not build Georgetown on their own. In 1837 the Barber brothers moved to the area from Dundas, the first of several generations who would contribute to the history of the community. In the 1850s the Barber Mills produced more wallpaper than any other plant in the province, and by the late 1880s the Barbers were the first to harness hydro electric power for manufacturing in North America. The paper mill and the ruins of the electric dynamo can still be seen along the Credit River, while John R. Barber's magnificent residence, Berwick Hall stands at the corner of Main and Park Streets. Other pioneers included James Young, grain and general merchant (the village's first reeve), and Philo Dayfoot, founder of the local leather industry.

Georgetown became the railroad centre of the area after the opening of the Grand Trunk Railway in 1856 and the Hamilton and Northwestern Railway some 20 years later. A third rail connection was the Toronto Suburban Railway, inaugurated in 1917. These brought plenty of business to hotels like the Railroad Exchange (still across from the railway station), and the Clark and Bennett Houses, where traveling salesmen would rub elbows at the bar with local farmers who had come into town to sell their produce and pick up supplies.

Georgetown continues to flourish today with a charming, older style downtown area radiating from the intersection of Mill and Main Streets, which has served as a setting for several motion pictures and television dramas in recent years.

From the days of the pioneers, Georgetown grew rapidly into an important community. Nearly 700 had arrived by 1845 and when Georgetown was finally incorporated as a village in 1864, there were about 1,400 people, rivaling Oakville as the largest community in Halton County. Over the following century the community grew steadily, becoming a town in 1922.

By the end of World War II, almost 4,000 people called Georgetown "home". This rapidly changed in the next few years after the arrival of Rex Heslop and the transformation of the farms on the eastern edge of town into the Delrex subdivision. A second population boom followed, with many residents now commuting to jobs in Malton and Toronto. By the time regional government was introduced in 1974, Georgetown had expanded into a sizable centre and today, Georgetown, Acton and surrounding Esquesing Township make up the larger municipality, the Town of Halton Hills.