[12] The development of the South Brooklyn area, including Carroll Gardens, was aided by the foundation in 1846 by philanthropists Henry Pierrepont and Jacob E. Leroy of the Hamilton Avenue Ferry.

Its purpose was to improve transportation to the newly created Green-Wood Cemetery, but horse car service, and later trolley lines, connecting to the ferry ran through Carroll Gardens, enabling businessmen who lived there to commute more easily to work in Manhattan.

Originally a private garden, it was purchased by the city in 1853, and was named after Charles Carroll in honor of his Maryland regiment, which had helped to defend the area during the Battle of Long Island in the American Revolutionary War.

[7][8][13] In 1846, surveyor Richard Butt planned gardens in front of the brownstone houses in the oldest section of the neighborhood when he developed it.

[4] The homes are set farther back from the street than is common in Brooklyn, and the large gardens became an iconic depiction of the neighborhood.

It was during this period, from the late 1860s to the early 1880s, that the area which is now the Carroll Gardens Historic District began to be developed.

[4] Carroll Gardens had long been considered to be part of either the larger area referred to as South Brooklyn, or the neighborhood known as Red Hook.

That neighborhood had an informal division in the 1930s and 1940s along Hamilton Avenue, with kids from south of the avenue, mostly of Italian descent, calling themselves "Hookers" or "Hookies" after Red Hook, and kids north of the street, mostly Irish, in what would now be Carroll Gardens called "Creekers" or "Creekies" after the now-drained Gowanus Creek.

[16] In the 1960s, young middle-class professionals began to be attracted to the Carroll Garden area due to its convenience to Manhattan, where many of them worked, and its growing reputation as a safe and quiet place to live.

This began the gentrification of the neighborhood, and a response from older residents, who did not appreciate these "hippie" newcomers who had no ties to the community.

[3][4] Today, Carroll Gardens is predominantly upper middle-class, while Red Hook, which had retained its working-class, waterfront ambiance, has only recently begun to feel the effects of gentrification.

[3] The Roman Catholicism of the Italian population is still evident in the many shrines, especially to the Virgin Mary, which can be seen in front gardens in the neighborhood, and the 70-year tradition of an Our Lady of Sorrows procession celebrating Good Friday continues.

[19] Carroll Gardens and the surrounding neighborhoods are sometimes referred to as "Little France" or "Little Paris" due to the growing French population.

[7] Based on data from the 2010 United States Census, the population of the Carroll Gardens/Columbia Street/Red Hook neighborhood tabulation area was 38,353, a change of 26 (0.1%) from the 38,327 counted in 2000.

[40] In 2018, an estimated 10% of Park Slope and Carroll Gardens residents lived in poverty, compared to 21% in all of Brooklyn and 20% in all of New York City.

Based on this calculation, as of 2018[update], Park Slope and Carroll Gardens is considered to be high-income and not gentrifying.

[37]: 11  Park Slope and Carroll Gardens has a relatively high population of residents who are uninsured, or who receive healthcare through Medicaid.

[37]: 14 The concentration of fine particulate matter, the deadliest type of air pollutant, in Park Slope and Carroll Gardens is 0.0089 milligrams per cubic metre (8.9×10−9 oz/cu ft), higher than the citywide and boroughwide averages.

[37]: 13  In Park Slope and Carroll Gardens, 15% of residents are obese, 6% are diabetic, and 22% have high blood pressure—compared to the citywide averages of 24%, 11%, and 28% respectively.

[37]: 10 Park Slope and Carroll Gardens generally have a much higher ratio of college-educated residents than the rest of the city as of 2018[update].

[48] Park Slope and Carroll Gardens's rate of elementary school student absenteeism is lower than the rest of New York City.

[37]: 6 The New York City Department of Education operates a number of public schools in the neighborhood: Patrick F. Daly (P.S.