James Kellum Smith FAIA (October 3, 1893 – February 18, 1961) was an American architect, of the Gilded Age architectural firm of McKim, Mead, and White.

From Towanda, Smith went on to Amherst College where he was a member of the Chi Psi fraternity and was graduated in 1915, with Phi Beta Kappa and Sigma Xi honors.

In June 1919, following a brief interruption in his studies on account of military service during World War I, he received a Bachelor of Science degree in architecture from the University of Pennsylvania.

He primarily designed academic buildings, but his last major work was the National Museum of American History.

The architectural firm McKim, Mead and White was contracted for the design of the new building on March 16, 1956.

In December 1957 the National Capital Planning Commission approved the site between 12th and 14th Streets on Constitution Avenue, just west of the Museum of Natural History.