Nathan Castellano advises clients on all aspects of doing business with and litigating against the federal government. His experience includes: bid protest and contract disputes; non-traditional contracting vehicles including Other Transactions; Freedom of Information Act (FOIA) matters; intellectual property issues including data rights and the SBIR program; small business and other set-aside programs; and general contract and grant compliance counseling.

Mr. Castellano studied procurement law extensively at the George Washington University Law School, working as a research assistant to Professor Steven Schooner and graduating as a Murray Schooner Procurement Scholar. Prior to joining the firm, he clerked for the Honorable Jimmie V. Reyna at the United States Court of Appeals for the Federal Circuit and worked as a legal consultant in the World Bank Office of Suspension and Debarment (OSD). He is a widely published author, with articles cited in leading treatises and used as course material.


  • Successfully protest and enjoin agency decision to cancel an FSS task order solicitation that was set aside for service-disabled veteran owned small businesses (SDVOSB) and resolicit the work under an all-large IDIQ vehicle without first conducting "Rule of Two" analysis. The Tolliver Group, Inc.; People, Technology and Processes, LLC v. United States, Nos. 20-1108C and 20-1290C, 2020 WL 7022493 (Fed. Cl. November 30, 2020).
  • Successfully protest solicitation for cloud computing services. Mythics, Inc.; Oracle America, Inc., B-418785, Sept. 9, 2020, 2020 CPD ¶ 295.
  • L3Harris Technologies in securing a judgment before the Armed Services Board of Contract Appeals in favor of L3Harris for a deficit arising from a pension segment closure under Cost Account Standard 413. L3Harris Technologies, Inc., ASBCA No. 62438 (June 2, 2020).
  • Successfully resolved a unique Assignment of Claims Act dispute through alternative means. LSQ Funding Group, L.C., v. United States, No. 18-1848C (Fed. Cl. 2020).
  • Successfully defended L3 Communications Integrated Systems L.P. against protest at the Court of Federal Claims. iAccess Techs., Inc. v. United States, 143 Fed. Cl. 521 (2019).
  • Successfully protested Blanket Purchase Agreement and task order awards under the Federal Supply Schedule at the Court of Federal Claims. Advanced Management Strategies Group, Inc./ReefPoint Group, LLC v. United States, 139 Fed. Cl. 404 (2018).
  • Successfully defended L3 Technologies against protest of award under the Compass Call program. The Boeing Company; Bombardier, Inc., B-417706, B-414380.2, August 25, 2017, 2017 CPD 274.
  • Successfully intervened in corrective action protest before the Court of Federal Claims, defeating motion for preliminary injunction. PricewaterhouseCoopers Public Sector, LLP v. United States, 126 Fed. Cl. 328 (2016).
  • Successfully challenged awardee's SDVOSB status before the Small Business Administration (SBA) Office of Hearings and Appeals (OHA). CVE Protest of: Advanced Management Strategies Group, Inc./ReefPoint Group, SBA No. CVE-120-P (2019).
  • Successfully protested scope of corrective action on behalf of CSRA LLC and obtained recommendation that agency reimburse protest costs. CSRA LLC—Costs, B-415171.3, August 27, 2018, 2018 CPD 307. Agency request for reconsideration denied. United States Marine Corps—Reconsideration, B-415171, December 14, 2018, 2019 CPD 5.
  • Successfully obtained corrective action in post-award protest of IDIQ award for unmanned aerial vehicles, Arcturus UAV, B-417550.1 (2019).
  • Successfully obtained corrective action in pre-award protest of task order award for cyber security support services. Blue Glacier Management Group, B-416647 (2018).
  • Successfully obtained corrective action in post-award protest. G2SF, Inc., B-416508.1 (2018).
  • Successfully obtained corrective action in pre-award protest of task order competition, CSRA LLC, B-414230.2 (2017).


Postscript III: Enhanced Debriefings: A Simple Strategy For a More Manageable Protest Process (pdf)
The Nash & Cibinic Report, Volume 35, Issue 8
Understanding Government Contracts Litigation Before the US Court of Appeals for the Federal Circuit
The End of Days for Litigation Over Contract Disputes Act Jurisdiction (pdf)
The Procurement Lawyer, ABA's Section of Public Contract Law, Vol. 56, No. 3
Federal Circuit Establishes Framework for Government Disputes with Software Companies (pdf)
The Licensing Journal, Vol. 41, No. 6
Fed. Circ. Ruling Establishes Framework for Gov't IP Disputes


Best Lawyers
"Ones to Watch"–Government Relations Practice (2021-2022)
Washington, DC Super Lawyers
"Rising Star"–Government Contracts (2020)


  • JD, The George Washington University Law School, 2015, highest honors, Order of the Coif
  • BA, Roanoke College, 2012, magna cum laude
  • District of Columbia
  • US Court of Federal Claims
  • US Court of Appeals for the Federal Circuit
  • United States Court of Appeals, Federal Circuit, The Honorable Jimmie V. Reyna
  • Adjunct Professor, The George Washington University Law School
  • Member, The George Washington University Law School Government Contracts Advisory Council

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