Castell Abner, III

Castell Abner

Castell Abner represents clients in matters related to commercial litigation. Castell is experienced in all phases of litigation, from writing pre- and post-trial motions, reviewing discovery, and drafting complaints and answers, to taking and defending depositions, negotiating settlements, and arguing hearings in state and federal courts. In addition to litigation, he helps promote his clients' interests through arbitration and alternative dispute resolution. Castell has represented clients in disputes concerning professional negligence, products liability, commercial real estate, general business litigation, consumer class actions, and securities fraud and conspiracy.

Castell's practice is informed by experience developed while working in the Delaware Department of Justice and clerking in the District of Columbia Superior Court. Prior to joining Venable, he was an associate attorney at a law firm where he represented architects, engineers, and other licensed design professionals. There, in addition to his active litigation caseload, he also counseled clients on stockholders' and operating agreements, stock and asset purchase agreements, bylaws, articles of formation, articles of conversion, founders' agreements, and professional service contracts.

Castell graduated cum laude from the American University Washington College of Law. While in law school, Castell earned several awards for his advocacy skills, including Best Opening Statement during the 2016 Judge Paul Joseph Kelly, Jr. Invitational Trial Competition hosted by Fordham University School of Law and the spring 2017 Highest Grade distinction in Civil Trial Advocacy—an award bestowed by the American University Trial Advocacy Department faculty. Prior to graduating from Washington College of Law, Castell graduated with a bachelor of business administration in accounting from Howard University, where he also served on the Board of Trustees and as president of the Xi Chapter of Kappa Alpha Psi Fraternity, Inc.


Representative Matters

Complex Litigation

  • Defended an international construction management firm against breach of contract, professional negligence, and fraud claims asserted by an international resort owner involving the use of insurance proceeds to reconstruct and erect a $185 million addition to an international resort
  • Defended a national architecture firm in a four-party dispute involving claims asserted by an international designer-builder alleging errors and omissions exceeding the $46 million renovation project's contingency reserves
  • Defended a structural engineering firm against third-party claims for contribution and indemnification asserted by a developer of a multi-residential new construction project in a six-party lawsuit, resulting in a complete defense verdict against the plaintiff's motions for temporary restraining order and preliminary injunction, and voluntary dismissal of the third-party claims against the structural engineer
  • Defended a structural engineering firm against third-party claims for contribution and indemnification brought by a general contractor facing first-party breach of contract and breach of warranty claims asserted by an owner of a condominium complex. Obtained dismissal with prejudice of the contribution claim on a motion to dismiss and negotiated voluntary dismissal with prejudice of the indemnification claim with no admission of liability or cash outlay
  • Negotiated voluntary dismissal for a regional engineering firm in a seven-party case involving claims for professional negligence and lost business profits

Government Contracts

  • Represented an architecture firm in an appeal before the District of Columbia Contract Appeals Board of an affirmative consequential damages claim asserted by the District's contracting officer
  • Defended a civil engineering firm against a multi-million-dollar third-party indemnification claim brought by a government agency arising from plaintiff general contractor's first-party breach of contract claims for recoupment of liquidated damages

Professional Liability

  • Negotiated a favorable settlement with no admission of liability on behalf of an Engineering News-Record (ENR) 100-ranked engineering firm alleged by a government agency to have committed violations of nuclear energy and environmental laws ordinarily carrying a penalty of $30,000/day
  • Defended a land surveying firm against breach of contract, professional negligence, and fraud claims asserted by two developers alleging the land survey firm failed to affirmatively notify the developers of construction defects made by the general contractor during construction
  • Negotiated a favorable settlement on behalf of a national architecture firm involving upstream professional negligence and breach of contract claims brought by the developer of two high-end mixed-use projects, and a downstream professional negligence counterclaim brought by the engineer of record
  • Negotiated a favorable settlement on behalf of a national structural engineering firm against a latent defect claim asserted by the owner of a commercial garage following the garage's collapse

Business Litigation

  • Secured recovery for an international architecture firm of a $300,000 fee from a national restaurant chain that had been cross-withholding payment on multiple projects subject to a master professional services agreement

Personal Injury

  • Defended a concrete batch plant distributor against a catastrophic personal injury action brought by a former employee of a concrete manufacturing plant alleged to have sustained injuries while performing maintenance on a concrete batch plant engineered and manufactured by the plant distributor
  • Defended a construction management firm in a personal injury action brought against five defendants involving cross-claims and third-party claims for contribution and indemnification arising out of the construction of a public roadway beautification project


  • Secured a complete release and indemnification of all past, present, and future claims associated with a historic landmark restoration project on behalf of an architecture firm involved in a breach of contract dispute with the public entity that owned the project; also secured a licensing fee from the owner of the project, which sought to replace the architect of record
  • Defended an engineering firm against a copyright infringement action involving alleged unauthorized use of remediation plans developed by a prior engineer




  • J.D. cum laude American University, Washington College of Law 2017
    • President, Mock Trial Honor Society
  • B.B.A. Accounting Howard University 2014

Bar Admissions

  • District of Columbia
  • Maryland
  • New York
  • Pennsylvania

Court Admissions

  • U.S. District Court for the District of Columbia
  • U.S. District Court for the District of Maryland
  • U.S. District Court for the District of Colorado
  • U.S. Tax Court

Clerk Experience

  • Honorable Elizabeth C. Wingo Superior Court of the District of Columbia
  • Honorable Yvone M. Williams Superior Court of the District of Columbia

Professional Memberships and Activities

  • Member, Venable Hiring Committee
  • Member, Howard University Board of Trustees, 2013 – 2014
  • Affiliate member, National Organization of Minority Architects


  • The National Black Lawyers, Top 40 Under 40, 2023
  • Capital Pro Bono Honor Roll, High Honors, 2022


Pro Bono

  • Member of team that achieved a six-figure settlement on behalf of a pro bono prisoner, brought against a prison healthcare system under Section 1983 for deliberate indifference to prisoner’s medical needs