Sean M. Sweeney

Phone: (414) 755-5020
Fax: (414) 271-3841

Areas of Practice:

Bar Admissions:

  • Wisconsin Circuit, Appellate, and Supreme Court
  • U.S. Federal District Court-Eastern District of Wisconsin
  • U.S. Federal District Court – Western District of Wisconsin
  • US Federal Bankruptcy Court – Eastern District of Wisconsin

Sean M. Sweeney’s practice focuses on business litigation, civil litigation, stock broker fraud, business transactional law, and real estate law. Sean has experience litigating business and civil disputes as both plaintiff’s and defendant’s counsel, helping buyers and sellers complete real estate transactions, as well as experience drafting contracts ranging from small business contracts to plow a parking lot to large corporation contracts dealing with operating and maintaining real estate.

Sean earned his Juris Doctor (JD) and Masters of Business Administration (MBA) from Marquette University. He earned his Bachelor of Science Degree in Business Economics from Northern Arizona University.

Sean and his team offer Flat Fees on complex business litigation cases. You can learn more about flat fee business litigation here. He also runs,  in which Halling & Cayo’s Securities Litigation team discusses securities fraud, stockbroker employment disputes, and FINRA arbitration.


    Thomas Moore Law Scholarship
    Sports Law Review, Editorial Staff
    Universidad de Costa Rica; San Jose, Costa Rica- Summer 2005
    Universitaria San Pablo CEU; Madrid, Spain- Summer 2006
  • MARQUETTE UNIVERSITY GRADUATE SCHOOL OF BUSINESS – Masters of Business Administration – May 2007
    Computer Information Systems Training
    SAS Business Intelligence Software
    EViews Quantitative Micro Software
  • NORTHERN ARIZONA UNIVERSITY SCHOOL OF BUSINESS – Bachelor of Science in Economics – May 2004
    Dean’s List: Spring 2001, Spring 2002, Fall 2002, and Fall 2003
    Centennial Scholarship
    National Student Exchange: Towson University; Towson, Maryland- Fall 2003

Honors and Awards:

  • Super Lawyers 2In 2011, 2012, 2013,  2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, and 2022 Sean was named to the Wisconsin Super Lawyers® Rising Stars list as one of the top attorneys in Wisconsin. No more than 2.5% of the lawyers in the state are selected to the list.
  • In 2012, 2013, 2014, and 2015 Sean was named to M: Milwaukee’s Lifestyle Magazine’s Leading Lawyers for Litigation. Leading Lawyers only selects those attorneys ranked in the top 2-5% for each category.
  • Avvo BadgeIn 2013, Sean was named to the Wisconsin Law Journals selection of Up-And-Coming Lawyers. Honorees are nominated by colleagues and selected by Wisconsin Law Journal editorial staff.
  • Sean maintains a rating of 10.0 “Superb” from  The rating is calculated using a mathematical model that considers elements such as years of experience, board certification, education, disciplinary history, professional achievement, and industry recognition.
  • In the 2024 edition of Best Lawyers in America®, Sean has been recognized for his excellence in Litigation – Securities. Recognition by Best Lawyers is based entirely on peer review.

Speaking Engagements:

  • Effectively Representing Client Issues in a Public Forum: Payment of Awards, Fiduciary Duty, and Forum Selection, PIABA Mid-Year Conference (2019)
  • Congressional Process: How a Bill Becomes a Law, PIABA Mid-Year Conference (2019)
  • Do’s and Dont’s of Group Arbitration Claims, PIABA Annual Conference (2017)
  • LLCs From a Litigator’s Prospective – Avoiding Litigation, Lorman Education Services (2013)
  • LLCs From a Litigator’s Prospective – Resolving Litigation, Lorman Education Services (2013)
  • Investment Fraud, from Wall Street to Main Street, Milwaukee Bar Association Presents (2012)
  • FINRA Mediation and Arbitration, State Bar of Wisconsin Litigation, Dispute Resolution & Appellate Practice Institute (2012)
  • Hidden Gems in Adobe Acrobat, Wisconsin Solo and Small Firm Conference (2011)
  • Ethics of Social Media, Wisconsin Solo and Small Firm Conference (2010)
  • Using Blogging as an effective communication tool, Wisconsin Bar Leaders Conference (2009)
  • Negotiating the Transition from Law School to Practice, Marquette University (2008)

View Written Articles

Professional Associations and Memberships:

  • Wisconsin Bar Association – Wisconsin Bar Litigation Section
  • Wisconsin Bar Association – Wisconsin Bar Business Law Section
  • Milwaukee Bar Association
  • National Sports Law Institute
  • Public Investors Arbitration Bar Association (PIABA)