Cleary Gottlieb Steen & Hamilton has hired veteran corporate lawyer Sebastian Alsheimer to lead its shareholder activism defense practice, as major law firms continue expanding teams to advise companies facing activist investors.

Alsheimer is joining Cleary as a partner from Wilson Sonsini Goodrich & Rosati, where he was also a partner, according to two sources familiar with the move. He will be based in New York and is set to begin in January.

Cleary and Alsheimer did not immediately respond to requests for comment.

At Cleary, Alsheimer will advise corporate clients including 3M, Honeywell, and BlackRock on shareholder engagement and defending against activist campaigns. Activism defense has become a growing area of focus for law firms as companies face increasing pressure from investors seeking strategic, governance, or leadership changes.

Alsheimer brings experience representing companies targeted by activist investors as well as advising activists themselves. During his three years at Wilson Sonsini, he defended companies such as Autodesk and BlackLine against campaigns by Starboard Value and other activist funds.

Before that, Alsheimer was a partner at Olshan Frome Wolosky, a firm known for representing hedge funds, where he worked with prominent activist investors including Elliott Investment Management and Starboard.

Cleary is the latest elite law firm to strengthen its shareholder activism capabilities. Earlier this year, Sullivan & Cromwell hired partners from Vinson & Elkins, Paul Weiss Rifkind Wharton & Garrison added a partner from Wachtell Lipton Rosen & Katz, and White & Case recruited from Cadwalader Wickersham & Taft.

Simpson Thacher & Bartlett has also expanded in the area, recently hiring a former senior shareholder advisory executive from Barclays Capital.

Alsheimer is part of a relatively small group of lawyers who specialize in activism defense, a group that includes Kai Liekefett of Sidley Austin, Shaun Mathew of Kirkland & Ellis, and Lawrence Elbaum of Sullivan & Cromwell.

Alsheimer holds degrees from Harvard University, the University of Oxford, Columbia University, and Yale University.