Marisa O’Sullivan

Marisa O’Sullivan


Marisa Jeffrey O’Sullivan is a rising star at Amy Stewart Law. In 2019 she was named Outstanding Young Lawyer of the year by the Dallas Association of Young Lawyers for her accomplishments as a tenacious advocate for her clients, and for the countless contributions she makes to Dallas and its legal community. 

Marisa is a quick study with a tireless work ethic who has the experience and know-how of a lawyer many years her senior. Her ability to focus the issues, identify the pressure points, and pinpoint opportunities for resolution have allowed her to achieve outstanding results for the firm’s clients. 

Marisa’s strong litigation background, coupled with her sound judgment, serves her clients well during the many hearings, depositions, mediations, and settlement negotiations she has handled.  She also has significant experience doing complex coverage analysis for her clients. Moreover, Marisa has primary responsibility at Amy Stewart Law for managing large-scale discovery. 

Marisa and her husband, Trevor, are world-travelers who recently hiked through Patagonia on their honeymoon. They are also proud dog parents to their rescue retriever Oz, named after St. Louis Cardinal great, Ozzie Smith. 


J.D., Southern Methodist University, Dedman School of Law, 2012, cum laude

  • Chief Counsel for the W.W. Caruth Child Advocacy Clinic, Fall 2011
  • Jackson Walker Moot Court, Board Member

B.A., University of Missouri, University Honors Program, 2009, magna cum laude

  • Study Abroad Exchange, University of Manchester, United Kingdom, Spring 2008
  • Study Abroad, Ghana, West Africa, Winter 2007

Court Admissions

Licensed in Texas

U.S. District Courts for the Northern, Eastern, and Western Districts of Texas

Representative Experience

  • Represented a technology company in coverage litigation against its commercial general liability and technology E&O insurers to recover $70 million in defense costs and $20 million in insurance policy proceeds for the settlement of an antitrust lawsuit; managed e-discovery involving more than a terabyte of underlying case data; case settled prior to trial
  • Represented a national seafood distributor in obtaining coverage for an eight-figure inventory loss
  • Represented a national alarm monitoring company as insurance coverage counsel in negotiations to settle a class action MDL alleging violations of the Telephone Consumer Protection Act and seeking $40 billion in damages; handled resulting coverage litigation against CGL and cyber insurers in Texas for failing to settle the case, while responding to parallel litigation initiated by the insurers in West Virginia; ultimately negotiated separate settlements with each insurer, including the negotiation of complex indemnity provisions
  • Completed a comprehensive cyber insurance assessment for an airline client, including analysis of 30+ risk scenarios against cyber policies, testing the coverage for each scenario, and making recommendations to resolve gaps in policy language
  • Engaged by a telecommunications technology company to challenge a cyber insurer’s denial of coverage for defense costs related to a series of high-stakes patent infringement and unfair competition lawsuits; secured payment of defense costs without coverage litigation
  • Completed a cyber program analysis for a quasi-governmental entity with annual revenue in excess of $1 billion including participation in risk roundtables with subject-matter experts in engineering, IT, marketing, and operations to identify risks; analyzed insurance and indemnity requirements in cybersecurity vendor contracts; and made recommendations to client and broker teams regarding cyber policy language
  • Represented a bar and restaurant in securing coverage for a multimillion-dollar personal injury claim
  • Engaged by a publicly traded, international retailer to favorably structure a commercial property and business income loss claim related to losses sustained to its Puerto Rico properties following Hurricane Maria

Awards and Recognition

  • Selected as a Texas Rising Star (2018 to 2021) by Super Lawyers as published by Thomson Reuters; Super Lawyers is a rating service of outstanding attorneys who have attained a high degree of peer recognition and professional achievement
  • Named one of the Best Lawyers in Dallas: Insurance Law by D Magazine (2021)
  • Named one of the Best Lawyers in Dallas Under 40 (2019 to 2021) by D Magazine
  • Named Outstanding Young Lawyer (2019) by the Dallas Association of Young Lawyers 
  • Selected by the Dallas Association of Young Lawyers as One to Watch (2016)
  • Dallas Association of Young Lawyers Foundation Fellow
  • Dallas Bar Association Foundation Fellow

Professional and Community Involvement

State Bar of Texas

Dallas Association of Young Lawyers 

  • Board Member, 2017 to present
  • Member, 2012 to present
  • Leadership Class and Project Steering Committee Member, 2015 to 2016
  • Membership Chair, 2012 to 2015

Dallas Women Lawyers Association 

  • Board Member, 2017 to present
  • Mentoring Circles Steering Committee Co-Chair, 2015 to present

Dallas Bar Association Trial Skills Section

  • Member, 2014 to present
  • Board Member, 2015 to 2016

Dallas Bar Association Tort and Insurance Practice Section

  • Member, 2014 to present
  • Board Member, 2015 to 2016

Attorneys Serving the Community, Member

National Women Lawyers Association

  • Dallas Conference Steering Committee Member, 2017 to 2018

Junior League of Dallas, Member, 2014 to 2017

Publications and Presentations

  • August 2019, “Solving Cybersecurity: How to Help Your Client Navigate the Minefield,” panel presentation to Dallas Association of Young Lawyers, In-house Counsel CLE, Dallas, Texas
  • April 2017, "Nuts & Bolts: Directors & Officers Liability Policies,” article for Journal of Texas Insurance Law, Volume 15, Number 1
  • November 2016, “Insurance 101 :: What Every Young Lawyer Should Know,” presentation for Dallas Association of Young Lawyers, Dallas, Texas
  • April 2016, Reprint of “E-Discovery :: What it Means to Us,” article for TYLA eNews, a Texas  Young Lawyers Association publication
  • November 2015, E-Discovery Outsourcing,” presentation for Global Society class, Sociology Department, Southern Methodist University, Dallas, Texas 
  • June 2015, “Mistakes in Corporate Insurance :: The Top 10,” article for Headnotes, a Dallas Bar Association publication
  • April 2015, November 2014, and April 2014, "E-Discovery Outsourcing,” presentation for Global Society class, Sociology Department, Southern Methodist University, Dallas, Texas 
  • February 2015, “The Skinny on Dodd-Frank for Insurance Counsel,” article for Consultant’s Corner for
  • January 2015,  “The Top Ten Corporate Insurance Pitfalls for Counsel to Avoid,” article for Consultant’s Corner for
  • December 2014, “Taking Inventory :: An Overview of Corporate Liability Insurance,” article for Consultant’s Corner for


Before joining the firm, Marisa gained valuable courtroom experience in her first year of practice, handling substantive hearings as first-chair, including disputes over jurisdiction, service, and due process. She also clerked for several well-respected trial boutique firms in Dallas, focusing primarily on complex commercial litigation. 

Judicial Clerkship

Law Clerk, Hon. Elizabeth Lang-Miers, Dallas Court of Appeals, Dallas, Texas, 2010