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Mark Theodore

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Mark Theodore is a partner in the Labor & Employment Law Department. He has devoted his practice almost exclusively to representing management in all aspects of traditional labor law matters throughout the U.S. He is Co-Chair of Proskauer’s Labor-Management and Collective Bargaining Practice Group.

Some recent highlights of his career include:

  • Successfully defended client against allegations that it had terminated a union supporter and isolated another. T-Mobile USA, Inc., 365 NLRB No. 15 (2017).
  • Successfully appealed NLRB findings that certain of client’s written policies violated the National Labor Relations Actions Act.  T-Mobile USA, Inc., 363 NLRB No. 171 (2016), enf’d in part, rev’d in part 865 F.3d 265 (5th Cir. 2017).
  • Represented major utility in NLRB proceedings related to organizing of planners.  Secured utility-wide bargaining unit. Bargained on behalf of grocery chain.  After negotiations reached an impasse, guided the company through lawful implementation of five year collective bargaining agreement.
  • Coordinated employer response in numerous strike situations including a work stoppage across 14 western states of the client’s operations.

Mark has extensive experience representing employers in all matters before the NLRB, including representation petitions, jurisdictional disputes and the handling of unfair labor practice charges from the date they are filed through trial and appeal. Mark has acted as lead negotiator for dozens of major companies in a variety of industries, including national, multi-unit, multi-location, multi-employer and multi-union bargaining. Mark has handled lockout and strike situations, coordinating the clients efforts.

In addition, Mark has handled hundreds of arbitrations involving virtually every area of dispute, including contract interest arbitration, contract interpretation, just cause termination/discipline, benefits, pay rates, and hours of work.

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On September 30, 2025, California Governor Gavin Newsom signed into law AB 288, which amends the state’s labor law and significantly expands the power of its Public Employment Relations Board (“PERB”) to cover private-sector employees currently under the exclusive jurisdiction of the National Labor Relations Board (“NLRB” or “Board”).  

Under…

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