Warren S. Koster

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Warren S. Koster



Warren S. Koster is a Partner in our New York City office. He also serves as Hiring Partner for the Northeast region, where he oversees associate attorney hiring endeavors. He comes to HBS with extensive experience in a wide variety of insurance defense litigation, including products liability, professional liability, medical malpractice, and general liability. Other areas of specialty include labor law, employment practices litigation, and insurance coverage issues.

After law school, Warren joined the Kings County District Attorney’s Office as a prosecutor, where he was named one of the youngest deputy chiefs of the trial bureau in the office’s history. He continued his public service as Counsel to the Criminal Justice Coordinator to the Office of the Mayor of the City of New York. In this capacity, Warren advised the mayor’s office regarding a variety of issues concerning the mayor’s legislative agenda as it related to the criminal justice system. After moving into private practice, Warren was a founding partner of Koster, Brady & Nagler, LLP.

Warren received his Juris Doctor from the University of Virginia and a Bachelor of Arts, cum laude, in International Relations from American University.



State Courts:

  • New York

U.S. District Courts:

  • U.S. District Court for the Eastern District of New York
  • U.S. District Court for the Southern District of New York

U.S. Supreme Court


  • J.D., University of Virginia
  • B.A., cum laude, International Relations, American University


  • American Bar Association
  • New York State Bar Association
  • Claims and Litigation Management Alliance (CLM)



Warren has published and lectured widely before industry and professional groups on issues related to many aspects of insurance defense litigation. His many seminar papers, topic presentations, and related memoranda include:

  • Sexual Harassment in the Workplace
  • Workplace Related Injuries
  • Unfair Claim Settlement Practices
  • New York No-Fault Law
  • Premises Liability: An Overview of Procedures and Issues in New York State Law
  • Actions Brought on Behalf of Decedents
  • Uninsured and Underinsured Motorist Coverage in New York
  • Workers’ Compensation or No-Fault: A Memorandum Outlining and Discussing the Interplay Between No-Fault Law and Workers’ Compensation Law
  • The Duty to Defend and Indemnify
  • New York Practice: A Memorandum Describing the Procedures and Structure of Law Practice in the State of New York
  • The Omnibus Workers’ Compensation Reform Act of 1996: An Overview
  • Avoidance, Investigation, Litigation and Adjustment of Bus Claims
  • The Duty to Defend and Indemnify Third-Party and No-Fault Claims

In the Press

HBS Announces New Regional Hiring Partners

Hall Booth Smith is excited to announce its six new regional Hiring Partners to oversee and aid in associate attorney recruiting in their respective regions. These attorneys will help to ensure HBS continues to attract top talent as the firm expands. About the Partners Atlanta Partner Jacquelyn Smith Clarke will oversee all efforts as Lead

New York’s Wrongful Death Statute Remains Untouched – For Now

In the waning hours of January 30, 2023 – the deadline to sign New York’s Grieving Families Act1 into law – Governor Kathy Hochul instead vetoed the legislation, which had passed both houses of the legislature with significant bipartisan support…

Hall Booth Smith Expands New York City Office with Addition of Four Attorneys

New York, NY – Hall Booth Smith, P.C. (HBS) has added four attorneys to its New York City office as the firm expands to serve its clients in the state of New York. Warren S. Koster is a Partner in our New York City office. He comes to HBS with extensive experience in a wide variety of insurance