Kahn emigrated from Estonia to the United States with his family at age four, becoming a naturalized citizen in 1914. A gifted artist, he forewent a merit scholarship to the Pennsylvania Academy of the Fine Arts to study architecture at the University of Pennsylvania. Trained in a rigorous Beaux-Arts tradition, with a heavy emphasis on drawing, Kahn earned his Bachelor of Architecture in 1924.

After completing his degree, Kahn worked in various firms in Philadelphia, including the offices of Paul Philippe Cret, his former studio critic at the University of Pennsylvania, before forming his own atelier in 1935. His earliest projects included collaborations with both George Howe, an early proponent of the International Style, and the modernist architect Oscar Stonorov and were largely comprised of designs for housing developments in Pennsylvania.

Kahn began his teaching career at Yale University in 1947, where he served as a professor and design critic at the Yale School of Architecture until 1957. During that time, he was also resident architect at the American Academy in Rome and traveled throughout Italy, Greece, and Egypt, recording abandoned ruins and historic architecture in sketches and drawings. The experience significantly influenced the idiosyncratic style for which Kahn would become known, his singular philosophy of architecture affected by his emotional response to the way light engaged with the ancient, monumental forms. Following his tenure at Yale, Kahn returned to Philadelphia to teach at the University of Pennsylvania. He was appointed Paul Philippe Cret Professor of Architecture, a position named in tribute to his mentor, which he held until his death in 1974.

From the mid-1950s onward‚ Kahn’s reputation and distinctive style were firmly established. His architecture was notable for its simple geometric forms and complex play between natural light and materials. Kahn’s first significant commission was the Yale University Art Gallery (completed in 1953). The building was constructed of masonry, concrete, glass, and steel, and it featured innovative engineering such as the tetrahedral ceiling and cylindrical staircase.

Kahn’s significant commissions include the Richards Medical Research Laboratories at the University of Pennsylvania (1957–65); the Salk Institute for Biological Studies in La Jolla, California (1959–65); the First Unitarian Church in Rochester, New York (1959–69); the Jatiyo Sangshad Bhaban National Assembly Building in Dhaka, Bangladesh (1962–74); the Phillips Exeter Academy Library in Exeter New Hampshire (1965–72); and the Kimbell Art Museum in Fort Worth, Texas (1967–72). Kahn’s Franklin D. Roosevelt Four Freedoms Park (1972–73) in Long Island City, New York, was completed in 2012.

The later years of Kahn’s career were distinguished by honors and awards, as well as important national and international commissions. He was elected a Fellow of the American Institute of Architects (AIA) in 1953. He was made a member of the National Institute of Arts and Letters in 1964 and became a member of the American Academy of Arts and Sciences in 1968. Kahn was awarded the AIA Gold Medal, the highest award bestowed by the association in 1971, as well as the Royal Gold Medal by the Royal Institute of British Architects (RIBA) in 1972.