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Mark R. Deethardt
Main image for Mark R. Deethardt

MARK DEETHARDT

Shareholder

,
New Orleans
T  504.556.4088
mrdeethardt@liskow.com
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Practices

  • Energy – Litigation
  • Litigation
  • Construction
  • Land Loss Litigation
  • Legacy/Oilfield Contamination Litigation
  • Pipeline Litigation
  • Appellate
  • Commercial Litigation

Blogs

  • The Energy Law Blog - Mark Deethardt

Assistant

Debra Leard

504.556.4121

“Our clients operate under numerous laws and regulations that raise complex legal issues. Regardless of the audience, I simplify those issues and make them easy to understand. This approach yields positive results for clients in and out of court.”

Overview

Mark is a litigator in the firm’s New Orleans office whose practice focuses on energy, environmental, and toxic tort litigation, as well as other litigation matters. 

Before joining the firm, Mark was an associate with a large New Orleans-based defense firm where he maintained a diverse litigation practice.  There, Mark routinely represented highly regulated national and regional financial institutions and banks in consumer financial services litigation involving single plaintiffs and class actions.  Mark represented a variety of other businesses – both large and small – in complex commercial litigation, property and insurance disputes, tax title recovery, and other tort and personal injury cases.  Mark is also experienced at protecting and preserving clients’ rights on appeal.  He has authored numerous successful merits briefs and defended writ applications before all Louisiana courts of appeals, the Louisiana Supreme Court, and the United States Court of Appeals for the Fifth Circuit. 

Mark graduated magna cum laude from LSU Law in 2012 where he was elected to the Order of the Coif and served as a Junior Associate and Senior Editor on the Louisiana Law Review.  As a Junior Associate on the Law Review, Mark received the Vinson & Elkins Award for Outstanding Student Case Note or Comment.  Before entering private practice, Mark served as a judicial law clerk to the Honorable Jeanette Theriot Knoll, former Associate Justice of the Louisiana Supreme Court. 

Involvement

Professional

  • IEL Advisory Board, 2024
  • IEL’s Young Energy Professionals Committee & Publication, The Energy Dispatch - Member
  • The Foundation For Natural Resources and Energy Law - Member
  • Louisiana Oil & Gas Association - Member
    • Legal Committee - Member
  • Federal Bar Association - Member
  • Louisiana Bar Association - Member
  • New Orleans Bar Association - Member

Community

  • Homeless Experience Legal Protection Program – Volunteer Attorney

Recognition

  • Best Lawyers® "One to Watch," 2023-2025
  • Louisiana Super Lawyers “Rising Star,” 2016-2018, 2020-2022
  • Louisiana State Bar Association, Leadership LSBA Class, 2015-2016

https://profiles.superlawyers.com/louisiana/new-orleans/lawyer/mark-r-deethardt/074489ff-8c27-4afe-b3ad-de6d2470c3ea.html?utm_source=074489ff-8c27-4afe-b3ad-de6d2470c3ea&utm_campaign=v1-slbadge-gray&utm_content=profile&utm_medium=www.liskow.com

Credentials

Education

  • Louisiana State University, Paul M. Hebert Law Center (J.D./D.C.L., magna cum laude, 2012)
    • Order of the Coif
    • Louisiana Law Review, Senior Editor, 2011-2012, Junior Associate, 2010-2011
    • Vinson & Elkins Award for Outstanding Student Case Note or Comment, 2010-2011
  • Loyola University New Orleans (B.A., English and History, magna cum laude, 2004)

Bar Admissions

  • Louisiana, 2012

Court Admissions

  • U.S. District Court, Eastern District, Louisiana, 2012
  • U.S. District Court, Middle District, Louisiana, 2012
  • U.S. District Court, Western District, Louisiana, 2012
  • U.S. Court of Appeals, Fifth Circuit, 2012
  • U.S. Bankruptcy Court, Eastern District, Louisiana

Clerkships

  • Law Clerk to the Honorable Jeannette Theriot Knoll, former Associate Justice of the Louisiana Supreme Court, 2012-2013

Presentations

  • “The Changing Landscape of Legacy Litigation: 2022 Developments,” Liskow's Energy Webinar Series, December 7, 2022

Publications

  • "Fifth Circuit Orders Remand to Allow Landowners’ Tort Claims to Proceed Against the Louisiana Department of Environmental Quality in State Court," Institute for Energy Law's The Energy Dispatch, December 2022
  • "Second Remand Order in Coastal Zone Management Cases Pending Before Fifth Circuit," Liskow & Lewis' The Energy Law Blog, January 2, 2020
  • "Fifth Circuit Opens Door to Removal Following Involuntary Dismissal of Non-Diverse Defendant," Liskow & Lewis' The Energy Law Blog, September 9, 2019
  • "2nd Circ. Case Highlights CAFA Home State Exception Trend," Law 360 Class Action, February 26, 2014
  • "Life After Gross: Finding a New Center for Disparate Treatment Proof Structures," 72 La. L. Rev. 187 (2011)

After Hours

"I was born and raised in New Orleans, and one of the things I love most about the city is its music culture.  Whether it’s going to see live music or collecting records, I am an avid music fan and try to incorporate music into my life on a daily basis.   My wife, Shannon, and I also love taking advantage of everything else New Orleans has to offer, including its restaurants, art galleries, and non-stop festivals.  We are both attorneys too, so when we are not in the office, we like to remain as active as possible by running, cycling, training, and everything in between."

WHAT’S TRENDING WITH Mark

  • News
    08.15.24
    118 Liskow Lawyers Recognized in The Best Lawyers in America® (BL Rankings) 2025
    5 minute read
  • News
    08.17.23
    114 Liskow Lawyers Recognized in The Best Lawyers in America® (BL Rankings) 2024
    5 minute read
  • Blogs
    02.06.23
    The Louisiana Supreme Court Issues New Decision Addressing Scope of Claims for Negligent Infliction of Emotional Distress Absent Physical Damage  
    4 minute read
  • News
    01.03.23
    Liskow Announces Six New Shareholders
    3 minute read
  • News
    08.18.22
    85 Liskow Lawyers Recognized in The Best Lawyers in America© (BL Rankings) 2023
    4 minute read
  • News
    01.12.22
    Forty-Eight Liskow Lawyers Selected to 2022 Louisiana Super Lawyers and Rising Stars, Thomson Reuters
    less than a minute
  • News
    08.19.21
    74 Lawyers Recognized in The Best Lawyers in America 2022 Edition
    3 minute read
  • News
    01.04.21
    Forty-One Liskow Lawyers Selected to 2021 Louisiana Super Lawyers, Thomson Reuters
    less than a minute
  • Insights
    01.02.20
    Second Remand Order in Coastal Zone Management Cases Pending Before Fifth Circuit
    less than a minute
  • News
    12.19.19
    Forty-Six Liskow Lawyers Selected to 2020 Louisiana Super Lawyers, Thomson Reuters
    less than a minute
View All
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