Promoting from inside, the National Gallery of Art has chosen Jeffrey Weiss to head its department of modern and contemporary art. He replaces Marla Prather, who after 13 years at the gallery is departing for New York to become the first curator of postwar art at the Whitney Museum.

Weiss, 41, has spent most of his career at the gallery. In 1987, as a doctoral candidate, he was awarded one of its Paul Mellon Fellowships, a plum that gave him two years in Paris and then a year of research at the gallery's Center for Advanced Study in the Visual Arts.

He was planning an academic career, Weiss said yesterday, "but after tasting museum work I was hooked."

His interest in art began when he was a little boy. He recalls being "mesmerized" by photographs of the sculptor Constanin Brancusi hewing wooden art in his eerie Paris studio. Weiss, who grew up in Bloomfield, N.J., received his BA from Dickinson College, and his master's and PhD degrees from New York University's Institute of Fine Arts. His doctoral thesis--"The Popular Culture of Modern Art: Picasso, Duchamp, and Avant-Gardism," was published in 1994 by the Yale University Press.

Weiss, who joined the staff as a research curator in 1991, became curator of 20th century art earlier this year. He organized the gallery's Mark Rothko retrospective in 1998, and is now working on "Pure Painting: Cubism--Futurism--Abstraction," a show about pre-1914 Paris, which will open at his museum in 2002.