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A decisive and empathetic advocate to help you realize your highest potential.


Aaron Knoll represents clients in high-stakes business litigation, clean-energy and environmental disputes, and matters involving governments and politics.

Aaron has experience fighting for businesses of all sizes in a wide range of commercial, consumer, and class-action disputes. He frequently advocates for developers in regulatory and litigation matters in the thriving renewable-energy industry. He defends governments and political actors against challenges to the integrity of their decisions and elections. And he conducts internal and agency investigations concerning FCPA and whistleblower risks.

To provide his clients with exceptional value and strategic counsel, Aaron actively listens to his clients to understand what matters to them and their businesses. He then analyzes their potential options and gives clear and practical advice on what to do moving forward. One client shared: "What sets Aaron apart is his ability to leverage his substantive expertise in ways that consistently account for his clients’ larger business goals."

Aaron’s genuine empathy and client-first approach get results. He has a track record of finding early solutions that avoid costly litigation, taking depositions that drive favorable outcomes, and crafting themes from complicated issues that persuade all audiences. Clients particularly turn to Aaron when they need a competitive advantage through the use of emotional intelligence or probability-based risk assessments.

Aaron has a passion for education and community service. He teaches legal writing at the University of St. Thomas School of Law. He is often invited to present at companies and CLEs on various topics, such as the evolving landscape of personal jurisdiction and the power behind weighted-risk analysis. And he serves as a trusted mentor to law students as they embark on their future endeavors.


  • J.D., University of St. Thomas School of Law, summa cum laude; Articles Editor, St. Thomas Law Review
  • B.A., University of Minnesota, History and Geography, with Distinction, magna cum laude 


  • Faegre Baker Daniels LLP, Associate
  • U.S. District Court for the District of Minnesota, Judge Paul A. Magnuson, Law Clerk 
  • Minnesota Supreme Court, Justice Christopher J. Dietzen, Law Clerk 


  • State of Minnesota 
  • U.S. District Court for the District of Minnesota
  • U.S. District Court for the Southern District of New York
  • U.S. District Court for the Northern District of Illinois
  • U.S. Court of Appeals for the Eighth Circuit


  • Federal Bar Association, Diversity and Inclusion Committee Co-Chair (2023-2024), Membership Committee Co-Chair (2022-2023), Legal Education Committee Co-Chair (2020-2022), Golf Tournament Committee Chair (2018-2020)
  • Minnesota State Bar Association
  • American Bar Association

Aaron's Practice Areas

  • Accountant Liability

    Greene Espel has extensive experience in a wide variety of disputes and problems confronting accounting firms, including the representation of Big Four, regional, and local accounting firms in audit, tax, and consulting negligence lawsuits, class action securities litigation, review board proceedings, and various federal and state regulatory and criminal matters. 

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  • Appellate

    “What’s next?” Greene Espel can guide you through the appellate process, providing an objective assessment of the pivotal issues, developing a strategy based on how appellate judges are likely to view a case in light of legal, institutional, and policy considerations, and advocating effectively.

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  • Class Actions

    Clients regularly turn to Greene Espel when faced with high-stakes, class-action litigation. Greene Espel attorneys have defended dozens of putative class actions in federal and state courts all across the country.

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  • Commercial Litigation

    Our business litigation practice embraces the wide variety of commercial disputes facing private and public companies today. Areas of particular expertise include intellectual property, antitrust, securities, employment, professional liability, and construction disputes.

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  • Energy and Environmental

    Handling environmental and energy disputes is a fundamental part of our practice. We defend lawsuits, give compliance counseling, and offer guidance in the face of legal and regulatory quagmires.

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  • Products Liability

    Defending products liability claims has been a cornerstone of Greene Espel’s practice since our founding in 1993. Manufacturers and other businesses turn to us when they face product defect allegations brought by individuals, by large groups of plaintiffs, or as putative class actions.

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  • Securities Litigation

    Institutional investors and public companies alike have turned to Greene Espel in high-stakes securities litigation: fraud cases, multi-million-dollar battles over the terms of securities, class actions, shareholder disputes, RMBS, and more. 

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  • Internal Investigations

    We leverage our experience to conduct sensitive and high-profile internal investigations for our clients. We also help clients navigate investigations to mitigate reputational, regulatory, and litigation risks. 

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  • Constitutional Litigation

    Constitutional litigation is a cornerstone of Greene Espel’s practice. We represent individuals, private businesses, and government entities where their actions raise constitutional issues.

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  • Elections and Redistricting

    Greene Espel takes on attacks to voting rights and democratic institutions—and wins. We take on lawsuits to tackle voter suppression, election subversion, and districting issues.

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  • Anti-corruption and FCPA

    Greene Espel rivals big firms with its experienced group of corruption and FCPA investigators and counselors. We help companies efficiently and effectively investigate allegations of corruption, assess their compliance programs, and present their best possible case to prosecutors and regulators. 

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Cases & Wins


Aaron has defended companies in complex and high-value commercial, consumer, and class-action litigation in federal and state courts:

  • Co-lead counsel representing Olmsted County in successful two-week jury trial of allegations of age, race, and gender discrimination, and retaliation in which the plaintiff sought $8.2 million in damages. The jury found no liability, discrimination, or retaliation on the part of the County. Jacob v. Olmsted, Case No. 55-cv-22-2347 (Third Judicial District, MN 2024)

  • Won jury verdict for wholesale distributor of hand sanitizer in breach-of-contract action in federal court

  • Pursuing claims on behalf of a global grain exporter for damages caused by the effective closure of the Chinese market to U.S. corn exports following the commercialization of certain GMO corn

  • Won dismissal of Section 20A claims against several defendants in a securities-fraud class action in the Southern District of New York
  • Defeated claims of whistleblower retaliation, tortious interference, and assault and battery against a large composites company in arbitration
  • Won dismissal of statutory and common law consumer-fraud claims against Fortune 500 company in putative nationwide class action involving dental products
  • Won summary judgment for Fortune 500 company against claims of product defects in fall-protection equipment
  • Successfully defended Fortune 500 company against allegations of breach of license agreement, fraud, and anti-competitive conduct
  • Successfully defended national creditor against statutory-fraud and business-tort claims and guided the client through system-wide risk-mitigation improvements
  • Compelled arbitration on behalf of major retail finance company after a bench trial
  • Obtained favorable settlement for national tile retailer in securities class action
  • Compelled arbitration in many putative consumer-protection class actions on behalf of financial institutions and retailers
  • Defeated or resolved in amicable settlement several opt-out cases pursuing Telephone Consumer Protection Act claims


Aaron has represented energy developers in navigating regulatory issues, litigating commercial and environmental disputes, and fighting for project approvals on appeal:

  • Successfully helped several developers of community solar gardens respond to and defeat co-location notices and other objections from Xcel Energy
  • Secured siting and permitting decisions for developers of solar gardens from Minnesota cities and counties
  • Successfully defended solar-garden developer in litigation over post-acquisition contract and fraud claims
  • Counseled Fortune 500 company in adapting to changed circumstances impacting renewable energy purchase agreements
  • Representing developer of Minnesota’s first copper-nickel mine in challenges to various permits for the NorthMet project


Aaron has helped local and state governments and political actors defeat obstructions to public actions and elections:

  • Won summary judgment for regional utilities commission against claims by withdrawn member seeking the commission’s assets
  • Defending cities against lawsuits seeking to overturn land-use and zoning decisions


Aaron has handled anti-corruption and other investigations for businesses faced with whistleblower allegations, regulatory action, and auditor scrutiny:

  • Represented filtration company to investigate allegations of accounting irregularities in Belgium
  • Represented large industrial client to investigate allegations of FCPA violations in China
  • Represented agricultural processor to investigate allegations of unsafe food handling practices
  • Represented commercial dairy producer to investigate allegations of FCPA violations in Mexico
  • Represented healthcare technology management organization to investigate allegations of FCPA violations in India


Lastly, Aaron maintains an active pro bono practice:

  • Defended a death-row inmate in Alabama state and federal post-conviction proceedings
  • Argued a criminal appeal on Fourth Amendment grounds in Minnesota state court
  • Sought expungements of criminal records for clients across Minnesota
  • Representing a client from Honduras seeking asylum in the United States based on sexual orientation and gender identity
  • Representing a client from Rwanda seeking asylum in the United States based on race, political opinion, and sexual orientation

Aaron's Recognition & Awards

  • 2023 Attorney of the Year, Minnesota Lawyer
  • 2022 Attorney of the YearMinnesota Lawyer
  • Listed in Best Lawyers: Ones to Watch (2021-2024)
  • Up and Coming Attorney, Minnesota Lawyer (2020)
  • Selected to Minnesota Rising Stars list, Minnesota Super Lawyers (2019-2023)
  • Dean's Award for Outstanding Teaching, University of St. Thomas School of Law  (2019)
  • North Star Lawyer for pro bono service, Minnesota State Bar Association (2016-2017)
  • Judge Earl R. Larson Law Student Award, Federal Bar Association (2012)
  • Mission Award for Excellence in Professional Preparation, University of St. Thomas School of Law (2010)

Aaron's Community Involvement

  • University of St. Thomas School of Law, Adjunct Faculty (2014-present)
  • University of St. Thomas School of Law Mentor Program, Mentor (2015-present)
  • American Bar Association National Appellate Advocacy Competition, Coach (2013-2015)


March 18, 2024
Client Win: Jury Rules in Favor of Greene Espel Client, Olmsted County, in Discrimination Suit
Read More
March 6, 2024
Client Win: Eighth Circuit Affirms Trial Win for Greene Espel Client Newsert
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December 31, 2023
University of St. Thomas School of Law, Adjunct Professor (2014-present)
February 16, 2022
Top 10 Tips for Better Using Legal Research in Writing and Oral Argument, Co-Presenter, Minnesota CLE


January 1, 2009
Residential- and Commercial-Scale Distributed Wind Energy in North Dakota, USA, Co-Author, Renewable Energy
"What sets Aaron apart is his ability to leverage his substantive expertise in ways that consistently account for his clients' larger business goals."
— Fortune 500 Client Contact

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