Marianna Knister Downer
Associate
201 St. Charles Avenue
40th Floor
New Orleans, LA 70170-4000
Main: 504.582.1111
Direct: 504.679.9824
Marianna Knister Downer is a civil litigator and trial attorney representing clients in a wide range of industries including energy & environmental, construction, and administrative law. Her practice at Gordon Arata extends to complex litigation, appeals, civil procedure, commercial litigation, and risk management.
Marianna obtained both her Juris Doctor and Graduate Diploma in Comparative Law from the Paul M. Hebert Law Center at Louisiana State University. While at the Law Center, Marianna was a Senior Associate on the Journal of Energy Law and Resources, served for two years on the LSU Student Bar Association, and was a recipient of the John P. Laborde Endowed Scholarship. Marianna graduated from the Manship School of Mass Communication at Louisiana State University in 2012 with her B.A. in Mass Communication with a concentration in Political Communication. Prior to obtaining her law degree, Marianna spent four years in Washington, D.C. working both on and off Capitol Hill with former Senator Mary L. Landrieu.
Practice Areas
Business Transactions & Corporate
Commercial Litigation
Commercial Transactions
Construction
Corporate Entity Formation, Governance and General Advice
Energy & Natural Resources
Environmental & Toxic Torts
Government Regulatory & Corporate Compliance
Insurance
Oil, Gas & Energy Litigation
Oil, Gas and Energy Litigation and Arbitration
Oil, Gas and Energy Regulatory
Real Estate
Renewable Energy
Experience
- Marianna second-chaired a five-day jury trial, successfully representing the her client against personal injury claims, resulting in a favorable 12-0 verdict.
Education
Louisiana State University Paul M. Hebert Law Center, J.D./D.C.L., 2019
Louisiana State University, B.A., 2012
Recognition
- Best Lawyers: Ones to Watch in America® for Commercial Litigation, Construction Law, Energy Law (2026 – present)
- Louisiana State Bar Association 2024 Young Lawyers Division Top 40 Young Lawyers Honoree
- Louisiana Super Lawyers (Thomson Reuters) – Rising Stars (2024 & 2025)
- John P. Laborde Endowed Scholarship Recipient
Affiliations
- Federal Bar Association
- Louisiana State Bar Association
- New Orleans Bar Association
- Mineral Law Institute Advisory Council (2024 – 2027)
- Women’s Energy Network – Southeast Louisiana Chapter Board of Directors – President-Elect (2025-2026), Communications Director (2024-2025), Public & Industry Relations Director (2022–2023) (2023-2024)
- Professional Landman’s Association of New Orleans – Member (2022 – Present)
- Hope Ignites New Orleans (formerly Boys Hope Girls Hope) Garden Gala Committee – Gala Co-Chair (2024 – 2025), Sponsorship Subcommittee Chair (2023), Committee Member (2022 – 2025)
- American Cancer Society’s Shuck Cancer – Junior Executive Board Member (2022 – 2024),
- Silent Auction Co-Chair (2022 – 2024), Silent Auction Advisor (2025)
- Pro Bono Project’s Justice for All Ball Committee – Committee Member (2020), Silent Auction Chair (2021, 2022)
News & Insights
News & Events
- Thirty-Three Gordon Arata Attorneys Recognized in the 2027 The Best Lawyers in America® List
- Twenty-Nine Gordon Arata Attorneys Recognized in the 2026 The Best Lawyers in America® List
- Twenty Gordon Arata Attorneys Selected to 2025 Louisiana Super Lawyers and Rising Stars
- Marianna Knister Downer and John Philip “J.P.” Graf Recognized as 2023 Top 40 Honorees by Louisiana State Bar Association Young Lawyers Division
- Twenty-Three Gordon Arata Attorneys Selected as 2024 Louisiana Super Lawyers and Rising Stars
- Gordon Arata Welcomes Associate Attorney Marianna Knister
Publications
- U.S. Supreme Court Sends Louisiana Pollution Suit to Federal Court: What It Means
- A Whale of a Tale: Rice’s Whale and the Impacts on Oil and Gas Leasing in the Gulf
- Hands Off My Fish: Louisiana Congressmen Endeavor to Expand Louisiana’s Offshore Authority
- Louisiana Legislative Update: Legislature Extends the Prescriptive Period for Tort Claims from One to Two Years
- Louisiana Moves Forward with Its FoCCuS on Carbon Capture and Sequestration
- To Compete or Non-Compete: The FTC’s Proposed Rule to the Latter
- Gone with the Wind: Louisiana’s Legislative Foray into Wind Energy Projects in the Gulf of Mexico
- Energy Companies Bid a Combined $192 Million in BOEM Oil and Gas Lease Sale for the Gulf of Mexico
- BOEM Resumes Oil and Gas Lease Sale for the Gulf of Mexico
- Balancing the SCALE: What the Passage of The SCALE Act Could Mean for Louisiana’s Energy Future
- A Short-Lived Legacy: Redefining Damage Awards in Oilfield Legacy Litigation
- This Land Is Your Land, This Land is Pipeline Land: The Supreme Court Rules in Favor of Congressional Delegation of Eminent Domain Authority to Pipeline Developers
Off the Clock
Outside of work, Marianna stays involved in both professional and personal community organizations, including serving on the board of the Women’s Energy Network South Louisiana Chapter and the Junior Executive Board for Shuck Cancer. Marianna and her husband, Stephen, and their daughter reside in New Orleans.