C. Fred Bergsten, director of the Peterson Institute for International Economics. (STEPHANIE KUYKENDAL/BLOOMBERG NEWS)

C. Fred Bergsten, a fixture in U.S. economic policy circles since the Nixon administration, is stepping down as head of the Peterson Institute for International Economics, the institute plans to announce Wednesday.

Bergsten, 70, has run the institute since its founding in 1981, when he was tapped by the German Marshall Fund to set up a think tank devoted solely to international economic problems.

It turned out to be a growth field: The institute now has a staff of more than 50, with two dozen senior fellows including prominent U.S. economists such as Carmen Reinhart, an expert in financial crises, and overseas experts who research issues such as the euro zone’s troubles and developing economies’ growing clout.

Bergsten himself has been a familiar face at congressional hearings, where in recent years he has been among the main critics of Chinese currency policies that he thinks create a disadvantage for U.S. manufacturers.

Despite that admittedly “hawkish” stance on China, Bergsten said he hopes his legacy is in creating an environment of free-flowing debate — where lectures on the likelihood of a euro-zone breakup can be followed by his own arguments for why the monetary union will remain intact.

The aim is to be “aggressively centrist,” Bergsten said. “We are not Keynesians. We are not Friedmanites. We are not supply-siders.”

A search is underway for a successor, the institute said. Bergsten said he will remain active as a fellow at the think tank.