President Barack Obama on Friday shook up his second-term economic team, announcing that long-term economic adviser Gene Sperling would be leaving at the end of the year and former top budget aide Jeff Zients would replace him.

Sperling, the director of the National Economic Council, has told friends he is leaving so he can spend more time with his family, which recently moved to California. Known for a frenetic work pace, he also was director of the NEC in the Clinton administration. His most recent stint as NEC director began in 2011, and he has coordinated all of Obama's economic policy. He spent the first two years of the administration as an adviser to then-Treasury Secretary Timothy Geithner.

Zients spent most of his career in the private sector, serving as a top executive at the Advisory Board Co. and Corporate Executive Board, among other firms. He joined the Office of Management and Budget in 2009 as a guru focused on how to improve how government works — one of the few top economic officials with deep business experience.