Thomas Whittlesey Leavitt, founding director of the Herbert F. Johnson Museum of Art for 18 years, a professor emeritus of the history of art and a recognized leader in the museum field, died Oct. 14 in Sanderson, R.I. He was 80.

Working with I.M. Pei, John Sullivan and Pei's architectural firm, Leavitt helped supervise the design and construction of the Bauhaus-inspired Johnson Museum building. He served as the museum's director from its inception in 1973 until his retirement in 1991. In 1997 he received the American Association of Museums' Distinguished Service to Museums Award, the field's most prestigious honor.

"Tom was a superb director, and what he did here has been the solid foundation for everything since then," said Franklin W. Robinson, the current director, who succeeded Leavitt in 1992. "He was also a man of kindness and civility, and it was a privilege to know him, and to be his successor in this great museum."

Leavitt came to Cornell in 1968 after serving as director of museums in Pasadena and Santa Barbara, Calif. As director of Cornell's A.D. White Museum of Art before the Johnson was built, he organized a pioneering show of Earth art, installed across campus in February 1969.

During his career, he organized more than 100 exhibitions and wrote numerous articles and catalog essays, ranging from American portraiture and the arts of New Guinea to Albert Bierstadt, Piet Mondrian and Cornell exhibitions of work by George Kolbe, Georgia Loring Brown and Agnes Denes, among others.

He was born in Boston Jan. 8, 1930, into a distinguished New England family that included the sculptor Bela Pratt. He received a B.A. in American literature in 1951 from Middlebury College, a master's degree in 1952 from Boston University in art history of the 19th and 20th centuries, and a Ph.D. in 1958 from Harvard University in the history of American painting and sculpture.

Leavitt was the first director appointed to lead the Museum Program of the National Endowment for the Arts (1971-72). He also served as president of the Association of Art Museum Directors (1977-78) and chair of the American Association of Museums (1982-85) and

After his retirement, he was interim director of the Rhode Island School of Design's Museum of Art (1992-93) and director of the Newport Art Museum and the Museum of Our National Heritage.

Leavitt held leadership, board and advisory positions in numerous arts organizations, including the American Art Alliance, American Federation of the Arts, Rhode Island Historical Society, National Air and Space Museum, National Museum Committee for Art Against AIDS and the New York State Council on the Arts.

He was also an avid sailor for more than 35 years, with interests in wooden boats and racing.

Leavitt is survived by his wife, Michele; five children and five grandchildren.

A memorial service will be held Saturday, Nov. 6, at 11 a.m. at the Newport Art Museum, Newport, R.I.