Andrew Rehfeld, a law professor long active in the Jewish community, was named the chief executive officer and president of the Jewish Federation of St. Louis.

Rehfeld, whose two-year contract will begin Sept. 1, will succeed Barry Rosenberg, 61, who after 20 years as the federation’s top executive will retire in August 2013. Rosenberg will assist Rehfeld with the transition, according to a statement.

Rehfeld, 46, has served on the boards of the St. Louis federation, the Jewish Community Relations Council of St. Louis, Sha’are Zedek Synagogue and the Hillel at Washington University, where he is an associate professor of political science and a professor of law.

“We are thrilled to have found a person of Andrew’s caliber to lead our organization and the whole St. Louis Jewish community into the future,” federation chair Robert Millstone, who led the search process, said in a statement. “Andrew brings us the intellect, passion, energy, collaborative skills, and the gift for communication that we were seeking in our new professional leader.”

Rehfeld was selected following an 18-month national search.