WASHINGTON — President Barack Obama will replace Gene Sperling, his chief economic adviser, with Jeffrey Zients, a top aide who has filled in as acting budget director and who led a White House effort to streamline government.

Zients will replace Sperling as director of Obama’s National Economic Council, a post Sperling held for nearly three years, serving as Obama’s economic whisperer during difficult fiscal wrangles with Congress. Sperling plans to leave Jan. 1

Obama announced the change today, describing Sperling as “one of my closest advisers and a close friend.” He praised Zients as an admired and respected aide in the White House with “a sterling reputation as a business leader.”

Zients is a long-time management consultant who joined the White House in 2009 as chief performance officer, heading an effort to streamline government and cut costs. Obama later chose him twice as acting director of the Office of Management and Budget and he has been considered for other top posts.

Sperling served in the same top economic post under President Bill Clinton.

He’s said to be leaving for personal reasons.