For eight years, Ben S. Bernanke, the former Federal Reserve chairman, was steward of the world’s largest economy. Now he has signed on to advise one of Wall Street’s biggest hedge funds.

Mr. Bernanke will become a senior adviser to Citadel, the $25 billion hedge fund founded by the billionaire Kenneth C. Griffin. He will offer his analysis of global economic and financial issues to Citadel’s investment committees. He will also meet with Citadel’s investors around the globe.

It is the latest and most prominent move by a Washington insider through the revolving door into the financial industry. Investors are increasingly looking for guidance on how to navigate an uncertain economic environment in the aftermath of the financial crisis and are willing to pay top dollar to former officials like Mr. Bernanke.

Mr. Bernanke joins a long parade of colleagues and peers to Wall Street and investment firms. After stepping down, Mr. Bernanke’s predecessor, Alan Greenspan, was recruited as a consultant for Deutsche Bank, the bond investment firm Pacific Investment Management Company and the hedge fund Paulson & Company.