In 1924, Mr. & Mrs. James Sibley Watson donated an initial $100,000 to the University earmarked for an addition to the Gallery. The architect was Lawrence Grant White of McKim, Mead & White, who had been architect for the Eastman Theatre. Ground was broken June 25, 1925 and the expanded Gallery opened on November 9, 1926.
The most prominent space in the addition was the Fountain Court, with flanking galleries on the second floor. The first floor saw the addition of an auditorium (called the "Little Theater"), children's museum, and an expanded library.