After 20 years of leading the Whitney Museum of American Art — and overseeing its move from Madison Avenue to the meatpacking district — Adam D. Weinberg is stepping down this fall as director. In an unusual joint announcement by the Whitney’s board, the museum also said it had already selected Weinberg’s successors: Scott Rothkopf, 46, the current senior deputy director and chief curator, who will become director on Nov. 1.

Rothkopf told The New York Times that in a way, he had been building toward this professional milestone his whole life. “I came to the museum when I was a kid with my grandparents to look at art and went back to Dallas and made Calder circus animals out of coat hangers. Then I worked as an intern here in college. So for me, there is a lifelong sense of intimacy with this museum.”

Weinberg said he felt he was leaving the Whitney in good hands, having worked closely with Rothkopf for a dozen years. Weinberg will become director emeritus and an honorary trustee.