The next step was the invention of a system in which the metal framework would support not only the floors but also the walls. This innovation appeared in the Home Insurance Building in Chicago, designed in 1883 by William Le Baron Jenney—the first building to employ steel skeleton construction and embody the general characteristics of a modern skyscraper. The subsequent erection in Chicago of a number of similar buildings made it the center of the early skyscraper architecture. In the 1890s the steel frame was formed into a completely riveted skeleton bearing all the structural loads, with the exterior or thin curtain walls serving merely as an enclosing screen.

In 1892 the New York Building Law made its first provisions for skeleton constructions. There followed a period of experimentation to devise efficient floor plans and aesthetically satisfying forms. In New York City the Flatiron Building by D. H. Burnham was constructed in 1902, the Metropolitan Life Insurance Tower in 1909, and the Woolworth Building, 60 stories high, by Cass Gilbert, in 1913. The last, with Gothic ornamentation, exemplifies the general tendency at that time to adapt earlier architectural styles to modern construction. The radical innovator Louis Henry Sullivan gave impetus to a new, bold aesthetic for skyscrapers. An excellent example is his design for the Wainwright building in St. Louis (1890-91). Frank Lloyd Wright also contributed his unorthodox vision to such structures as the Price Tower (1953) in Bartlesville, Okla.

In 1916, New York City adopted the Building Zone Resolution, establishing legal control over the height and plan of buildings and over the factors relating to health, fire hazard, and assurance of adequate light and air to buildings and streets. Regulations regarding the setting back of exterior walls above a determined height, largely intended to allow light to reach the streets, gave rise to buildings whose stepped profiles characterize the American skyscraper of subsequent years.

With the complex structural and planning problems solved, architects still seek solutions to the difficulties of integrating skyscrapers with community requirements of hygiene, transportation, and commercial interest. In New York during the 1950s, public plazas were incorporated into the designs of the Lever House by Gordon Bunshaft and the Seagram Building of Mies van der Rohe. These International style buildings are also examples of the effective use of vast expanses of glass in skyscrapers. More recently, numerous skyscrapers have been constructed in a number of postmodern modes.

By convention, a skyscraper is a building that is used primarily for human habitation with the greatest majority of its height divided into occupiable floors. Freestanding structures used primarily for broadcasting or sightseeing are classified as towers. The height of a building is measured from the sidewalk level of the main entrance to the structural top of the building. This includes spires but does not include television antennas, radio antennas, or flagpoles. By this definition the tallest building is the Burj Khalifa, Dubai, United Arab Emirates, which was topped off in 2009 at 2,717 ft (828 m) and 160 stories; it is also tallest structure in the world. Taipei 101, Taipei, Taiwan, is the second tallest at 1,671 ft (509 m) and 101 stories in 2003. The twin Petronas Towers (opened 1997) in Kuala Lumpur, Malaysia, are the third tallest; 88 stories high and topped by twin spires, they stand 1,483 ft (456 m) tall. The Willis Tower (opened 1974, formerly the Sears Tower) in Chicago is the tallest building in the United States; its 110 stories rise 1,454 ft (443 m) with an additional 253 ft (77 m) for the television antenna on top.

Among the highest New York City skyscrapers are the Empire State Building, with 102 stories, 1,250 ft (381 m) high; the Chrysler Building, with 77 stories, 1,048 ft (319 m) high; 60 Wall Tower, with 67 stories, 950 ft (290 m) high; and the GE (formerly RCA) Building in Rockefeller Center, with 70 stories, 850 ft (259 m) high. The former World Trade Center, which was the tallest building in the city until it was destroyed (Sept., 2001) by a terrorist attack, had two unstepped, rectangular towers of 110 stories each, one 1,362 ft (415 m) and the other 1,368 ft (417 m) high.