University of Calgary, Juris Doctor


University of Calgary, BA, Philosophy


Mount Royal University, Diploma in Jazz Performance

The Advocate's Society 

Calgary Bar Association 

Canadian Bar Association 


Best Lawyers
Ones to Watch
Appellate Practice (2024) 


Best Lawyers
Ones to Watch
Corporate & Commercial Litigation

David J. Marshall

David Marshall joined JSS Barristers in 2016, after articling and working as an associate at a large national firm. David’s practice primarily focuses on complex business disputes, both in Court and through arbitration. David represents clients as lead counsel before all levels of court in Alberta.

David’s practice in complex commercial litigation focuses on oil and gas, securities, shareholder, employment, insurance, and general corporate/commercial disputes. David also has experience in the areas of administrative, public and regulatory law, professional negligence and discipline, defamation, and franchise litigation. David has significant experience at the appellate level, having acted as lead counsel before the Court of Appeal of Alberta and in pursuing and responding to applications for leave to appeal to the Supreme Court of Canada. David also has experience with and has appeared before the Supreme Court of British Columbia and has experience with the Saskatchewan Court of King’s Bench.

David approaches disputes from a risk management perspective, and believes that dispute resolution, properly managed, is a value proposition for clients. David relishes the demands of complex litigation in a fast-paced team environment. David particularly enjoys working with and against experts in complex disputes involving highly technical subject matter.

Awards & Recognition

In 2022 and 2023, David was recognized by Best Lawyers Canada in their 2023 and 2024 lists of Ones to Watch, awarded to associates for their outstanding professional excellence in corporate & commercial litigation.  In 2023 David was further recognized on the 2024 Ones to Watch list for his appellate practice.

Representative Experience

David is acting as lead counsel for a NYSE-listed company in a multi-million dollar dispute with a local agent regarding termination of a distribution agreement. This matter involved pursuit of injunctions in multiple jurisdictions with complex issues regarding equity, property law, the interpretation of unwritten contracts, and other commercial issues. The matter went through two weeks of trial in early 2023.

From November 2022 to January 2023, David was a key member of the JSS Barristers team that represented TotalEnergies EP Canada Ltd. (TEPCA) in a high-stakes, exceedingly fast-tracked dispute regarding a right of first refusal (ROFR) by TEPCA over a $1 billion transaction through which Suncor Energy Inc. (SEI) would acquire the entire interest of Teck Resources Limited (Teck) in the Fort Hills Oil Sands Project.  The intended closing date for the transaction was 28 January 2023.  TEPCA alleged that there was no valid ROFR notice issued and that, as a result, the transaction would be void. The issues included the extent and nature of the duty of good faith in Canadian contract law and whether that duty trumps conflicting contractual clauses, the test and nature of the evidence necessary to have the Court determine that a ROFR notice is invalid, and many other issues. The dispute was referenced in the media.

David played a significant role in a complex commercial arbitration involving a joint venture in the midstream market in Alberta. This dispute involved over $60 million and was to be resolved through a multi-week hearing before an arbitral panel in 2022, before being resolved by settlement shortly before the hearing. David’s role included working closely with engineering experts on highly technical chemical engineering, pipeline and production volume forecasting, facilities management, and damages issues.

David is acting for an investor in an oppression claim involving a multi-million dollar investment in convertible debentures in advance of a $100+ million divestiture transaction. This matter involved successfully appearing on short notice to protect the client’s interests during the plan of arrangement proceedings.

David has acted as counsel on a number of professional negligence matters, including several complex disputes involving appearances before the Court of Appeal. These matters also included pursuing and responding to leave to appeal to the Supreme Court of Canada. David has considered complex issues in this area including limitations, causation, the Charter, the right to judicial review of professional regulation decisions, contributory negligence and apportionment of liability, punitive damages, and costs.

In 2023, David obtained a stay pending appeal of a health regulator's disciplinary decision, which involved first-instance consideration of recent amendments to the Health Professions Act regarding sexual abuse of patients (2023 ABKB 522).  


David obtained his J.D. from the University of Calgary in 2014. During his studies, David earned many awards and scholarships, including for highest standing in property law and advanced oil and gas law, and twice made the Dean's List. Additionally, David volunteered at Student Legal Assistance throughout his tenure at law school.

Prior to law school, David obtained a Diploma in Jazz Performance from Mount Royal University, in Calgary. Following that, David spent several years playing and teaching music professionally in the Calgary area. Later, David obtained a Bachelor of Arts in Philosophy (with distinction) from the University of Calgary before attending law school.


When not practicing law, David is spending time with his family, enjoying the local culinary scene, or golfing. On top of that, he is still involved in several ongoing musical endeavors. David is a proud Calgarian, his southern Albertan family roots stretching back more than 100 years. David is also a lifelong (and suffering) fan of the Calgary Flames.


"Court provides Guidance on Appeal and Stay Procedures under Health Professions Act"

JSS Barristers.ca, January 30, 2024
Co-Author (with Giovanni Perri) 

"Court Directives on Generative AI: Recent Attempts at Balancing Concerns with Ethical Duties and Effective Representation"

JSSBarristers.ca, July 14, 2023

"The Uber Decision: Justice Come Heller High Water? Litigating Unconscionability"

JSSBarristers.ca, July 14, 2020
Co-Author (with Bryan C. Duguid KC, FCIArb)

"The Uber Decision: Justice Come Heller High Water? Improvident Bargain"

JSSBarristers.ca, July 8, 2020
Co-Author (with Bryan C. Duguid KC, FCIArb)

"The Uber Decision: Justice Come Heller High Water? Unequal Bargaining Power"

JSSBarristers.ca, July 2, 2020
Co-Author (with Bryan C. Duguid KC, FCIArb)