Internationally celebrated for such iconic designs as the Louvre Pyramid in Paris and the Bank of China Tower in Hong Kong, I. M. Pei founded the firm in 1955 with Henry N. Cobb and Eason H. Leonard, providing vigorous leadership for thirty-five years, until his retirement in 1990. His numerous contributions to the profession have been recognized with the Pritzker Architecture Prize, the AIA Gold Medal, and the Royal Gold Medal of the Royal Institute of British Architects, among many other honors.

Born in Guangzhou, China, in 1917, Ieoh Ming Pei came to the United States at the age of seventeen to study architecture. He received a bachelor’s degree from MIT in 1940 and a master’s in 1946 from the Harvard Graduate School of Design, where he remained as an assistant professor until 1948.

That year he accepted an invitation from the developer William Zeckendorf, Sr., to become the director of architecture at Webb & Knapp, a New York real estate development company. In this role, with a team of young designers recruited from Harvard, Mr. Pei embarked on a series of large-scale architectural and planning projects across the country, including Mile High Center in Denver (1956), the Southwest Washington Urban Renewal Plan (1962), and Society Hill in Philadelphia (1964).

In 1955, with colleagues Henry Cobb and Eason Leonard, Mr. Pei formed the partnership of I. M. Pei & Associates. Formally separating from Webb & Knapp in 1960, the firm became known as I. M. Pei & Partners in 1966 and Pei Cobb Freed & Partners in 1989.

Mr. Pei’s personal architectural style blossomed with his design for the National Center for Atmospheric Research in Boulder, Colorado (1967), a sculptural complex composed of cast-in-place concrete, a material in which the firm had developed special expertise. At this time he also embarked on a series of museum projects—the building form with which he is now most closely identified—culminating in the East Building of the National Gallery of Art in Washington (1978) and the John Fitzgerald Kennedy Library in Boston (1979), both of which gained broad national attention. In all, he has designed more than a dozen museums, most notably the Grand Louvre in Paris (1989); Miho Museum in Shiga, Japan (1997); Suzhou Museum in Suzhou, China (2006); and the Museum of Islamic Art in Doha (2008).

Other institutional projects by Mr. Pei include churches, hospitals, and municipal buildings as well as academic facilities and libraries. Among his skyscrapers are the 72-story Bank of China Tower in Hong Kong (1989), whose distinctive prismatic design is engineered to withstand typhoon-force winds, and the Four Seasons Hotel in Midtown Manhattan (1993), which reinvents the classic grand hotel.

Having become an American citizen in 1954, Mr. Pei did not return to his homeland until the late 1970s, when he was commissioned to design the Fragrant Hill Hotel in Beijing (1982). Like Suzhou Museum, his only other built work in mainland China, the project brings advanced technology to bear on indigenous building practice, forming the basis for a new, distinctly Chinese form of modern architecture.

After his retirement from the partnership in 1990, Mr. Pei collaborated with the firm on several projects, including the Four Seasons Hotel, the Miho Museum, the Deutches Historisches Museum in Berlin (2003), and the Musée d’Art Moderne in Luxembourg (2006).

Beloved in France for his modernization of the Louvre, Mr. Pei was awarded the Grande Médaille d’Or of the Académie d’Architecture de France and was a Commandeur of the Ordre National de la Légion d'Honneur. For his service to the United States, he received the Presidential Medal of Freedom, the Medal of Arts from the National Endowment for the Arts, and the Lifetime Achievement Award from the Smithsonian Institution’s Cooper-Hewitt, National Design Museum.

Mr. Pei held honorary doctorates from Harvard, Columbia, and Brown, among other universities in the United States and abroad. A fellow of the American Institute of Architects and Royal Institute of British Architects, he was elected to the American Academy of Arts and Sciences, the National Academy of Design, the American Academy of Arts and Letters, the Académie d'Architecture de France, and Britain’s Royal Academy of Arts.

I. M. Pei died in New York City in May 2019.