SAN FRANCISCO — Greenberg Traurig has lured the managing partner of Winston & Strawn’s San Francisco office to build out its practices in Northern California.

Charles Birenbaum started Tuesday as a partner in Greenberg’s labor and employment practice and as chair of Northern California — a new position created by the firm to “propel the growth of their Northern California assets,” Birenbaum said. He will manage 70 attorneys across the San Francisco, Silicon Valley and Sacramento offices by coordinating with the office managers and department heads.