Designed by architect Morris Lapidus in the Miami Modern style, in association with the firm of Harle & Liebman, the building occupies the southeastern corner of Lexington Avenue and 51st Street.

Loew's Theatres announced plans to replace the theater in early 1960, and a groundbreaking ceremony for the hotel took place on June 21, 1960.

[3] Entrances to the New York City Subway's Lexington Avenue/51st Street station, served by the 6, <6>​​, E, and ​M trains, are adjacent to the north side of the building.

[16] At the time of the Summit Hotel's construction, other "unconventional" buildings like the Solomon R. Guggenheim Museum, TWA Flight Center, and Begrisch Hall were being built in New York City.

[18][19][20] To distinguish the hotel from other nearby buildings, Lapidus used a color palette of dark-green mosaic tile and turquoise brick.

Lapidus said he was inspired by the green-blue color of the McGraw Hill Building at 330 West 42nd Street, designed by Raymond Hood.

[23] The facade of El Gaucho was depressed beneath the main entrance and contained "molded stone-like lattice work" with small stained-glass inlays.

[22] The easternmost section of the base on 51st Street is clad with concrete panels and contains a loading dock and a parking garage entrance.

[34][35] The Gaucho Steak House was designed with metal light fixtures shaped like steer skulls; walls with gold naugahyde; and ceiling beams with animal motifs.

[28] An open staircase led from the lobby to the restrooms and ballroom; it was decorated with a mural that, according to Lapidus, was an "abstraction" intended to evoke the feeling of approaching a summit.

[34] The elevator doors were decorated with porcelain enamel designs in a blue, green, turquoise, purple, and black color palette.

The hotels accommodated crowds who visited the Grand Central Palace exhibition hall and, after the 1950s, the headquarters of the United Nations.

[32] Loew's hired Claudius C. Philippe, head of sales and catering at the Waldorf Astoria, as the Summit's first executive vice president in early 1961.

[63] The Summit spent $200,000 to run advertisements in movie theaters, on radio stations, and in European and South American newspapers.

[23][64] By the time the Summit Hotel opened, its staff could speak 16 languages, "including two dialects of Chinese, Hebrew, and Swahili".

[62][65] The Summit Hotel opened the next day, August 1, with a ceremony attended by Filipino diplomat Carlos P. Romulo, deputy mayor Paul R. Screvane, and Commerce and Industry Department official Robert W.

[23][43] Though the hospitality industry in New York City had reportedly reached a 20-year low in 1960, the Tisch brothers expressed confidence that the Summit would attract guests with its unconventional design and multilingual staff.

[5][37][38] The hotel also applied for a cabaret license that November, having received a $25 fine for offering unlicensed musical entertainment at its restaurants for four months.

[75] By the end of this decade, the Summit sought to attract business travelers, and it started providing free continental breakfasts to corporate guests.

[28] A joint venture of Highgate Holdings, Whitehall Real Estate Funds (owned by Goldman Sachs), and Rockwood Capital LLC bought the hotel in July 2003.

The joint venture did not intend to change the Metropolitan Hotel's facade, but they did renovate all the rooms, as well as the bar, restaurant, windows, and penthouse.

[79][87] RLJ spent another $25 million on renovating the hotel, redecorating all rooms with geometric motifs based on Lapidus's original design.

[94] Female students living at the Webster Apartments in Hudson Yards, Manhattan, were relocated to 569 Lexington Avenue.

[95] In addition, the City University of New York leased dormitory space at the building during the redevelopment of its Brookdale campus in Kips Bay, Manhattan.

[28] The Times wrote that the Summit's "curved sea-foam-blue facade and a sign straight out of The Jetsons" made it an object of derision.

[29] Ada Louise Huxtable believed the Summit was "a glittering display of gaudy confusion" and that its colorful design could not conceal the hotel's "small spaces and hard-headed economies".

[28][38] Lynes criticized the hotel's facade as having an "underwater" appearance, and he thought the vertical sign befitted "any motel on the road from Dallas to Fort Worth or any bowling alley in Paramus, N.J.".

[38] Time magazine called the interior a mixture of "Bronx baroque and Mexicali modrun";[38][41] on the other hand, "if judicious use of space is indeed essential, the Summit rates high.

[23][99] Time said the "S" shape was a "welcome change from Manhattan’s orange-crate regularity", even though the magazine's critic personally disliked the green facade.

[102] Herbert Muschamp claimed in 2002 that some of the criticism may have been motivated by bigotry, saying: "I suspect that for many who liked the Summit, including myself, the Jewishness, not the ersatz South Americana, helped account for the appeal.