Over the succeeding years, this plan would result in the extension of subway lines to far-flung areas of the Bronx, Brooklyn, and Queens, making land accessible for lower-density development that would help disperse the congested population of the inner city.

[8] McAneny was the driving force behind the city's 1916 comprehensive zoning resolution, which for the first time provided residential neighborhoods with the possibility of legal protection against land-use change.

He supported the Fifth Avenue Association, a business group that advocated for zoning to stabilize land values, and created the committees of the Board of Estimate that would develop the resolution.

"[10] McAneny and reformers with the most comprehensive view of city planning advanced regulatory schemes that would limit the height and bulk of buildings, occasionally going so far as to propose architectural review of exterior facades.

They promoted a concept known as excess condemnation, which would have allowed the city to capitalize on its own infrastructure investments by acquiring more land than needed for new streets and subways and in order to consolidate small parcels and sell them for redevelopment at higher values.

[8] As Manhattan Borough President, George McAneny helped secure funding from the philanthropist Olivia Slocum Sage for the restoration of New York's historic City Hall, built in 1811.

[16] In 1939, McAneny helped convince the Secretary of the Interior, Harold Ickes, to designate an 1830s neoclassical building that stood on the site where George Washington had been inaugurated as president in 1789, as a national historic shrine.

As president of the Regional Plan Association, he forcefully advocated against the construction of one of Moses's pet projects, a gigantic Brooklyn–Battery Bridge from the toe of Manhattan to Brooklyn that would have overshadowed Battery Park and blocked views of New York Harbor.

[19] Moses, as Parks Commissioner, then determined to demolish the Battery's historic fort, which at the time was being used as a public aquarium, supposedly because tunnel construction would undermine its foundations, but more likely simply to take revenge against the preservationists.

McAneny, who in 1942 became president of New York's main preservation society, assembled a group of leading citizens to battle Moses in the courts, in the press, and in federal, state, and local legislative bodies.

In 1949 the city and state finally agreed to transfer the structure to the federal government, and the fort, now known as Castle Clinton, was preserved and restored as a national historic site.

[20] During the Castle Clinton campaign, McAneny and his National Park Service contacts began to develop an idea for a new organization that would be able to draw on private resources to preserve historic buildings nationwide.