FILE - In this Feb. 14, 2012 file photo, then-acting Budget Director Jeffrey Zients testifies on Capitol Hill in Washington. A White House official says Gene Sperling, President Barack Obama's top economic adviser, plans to leave in January and will be replaced by Zients, who has twice served as White House acting budget director. (AP Photo/J. Scott Applewhite, File)  Jeffrey Zients shown in February 2012. (J. Scott Applewhite/AP)

President Obama will announce Friday that his top White House economic adviser, Gene Sperling, will leave at the end of the year and be replaced by Obama’s former budget director, Jeff Zients, a White House official said.

National Economic Council director Gene Sperling, who also played that role in the Clinton administration, will be leaving so he can join his wife in California. He spent the first two years of Obama's first term as a senior adviser to then-Treasury Secretary Timothy F. Geithner and later moved to the White House, where he coordinates economic policy.

Sperling is known for keeping a frenetic pace and long hours in the White House, and friends were surprised he would consider leaving the place he has spent much of his professional life. As NEC director, Sperling helped shape the full range of Obama’s economic policies, and generally advocated for a more aggressive stance toward preserving government spending and the social safety net. A Michigan native, he has particularly focused on boosting manufacturing.

Zients, who spent his career in business, served twice as acting budget director in the Office of Management and Budget. He was considered for other slots, including U.S. trade representative and commerce secretary, but left the administration this year shortly after Obama tapped Sylvia Mathews Burwell as his new budget director. He will not have to be confirmed for his new post, as Sperling's successor.