Emmanuel Louis Masqueray (1861–1917) was a Franco-American preeminent figure in the history of American architecture, both as a gifted designer of landmark buildings and as an influential teacher of the profession of architecture.
He was born in Dieppe, France, on September 10, 1861 to Charles-Emmanuel and Henriette-Marie-Louise Masqueray, née de Lamare. He was educated in Rouen and Paris. Having decided to become an architect, he studied at the École des Beaux Arts, Paris, as a pupil of and , and was awarded the Deschaumes Prize by the Institute of France. He also received the Chandesaigues Prize. While in Paris, he also served on the Commission des Monuments Historiques.
He came to the United States in 1887 to work for the firm of Carrère and Hastings in New York City; both John Mervin Carrère (November 9, 1858 – March 1, 1911) and Thomas Hastings (1860–1929) had been fellow students with Masqueray at the École des Beaux Arts. While in their employ, Masqueray created the watercolor elevation of the Ponce de Leon Hotel in St. Augustine, Florida. Other important work on the boards during his time with the firm included the Hotel Alcazar, St. Augustine, Florida, 1887, now the Lightner Museum, The Commonwealth Club, Richmond, Virginia, 1891, and the Edison Building, New York City, 1891 (razed). Five years later, he joined the office of Richard Morris Hunt (1827–1895), the first American architect to attend the École des Beaux Arts; in Hunt's firm he helped design many notable buildings including the Elbridge Gerry residence in Marblehead, MA, the William Astor house on Fifth Avenue in New York City, and Ochre Court in Newport, Rhode Island. It is likely that he made major contributions to the design of the Metropolitan Museum of Art in New York City. He also contributed to the design of The Breakers for Cornelius Vanderbilt II in Newport, Rhode Island.