Our Team

Mark O'Shaughnessy
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Mark is a partner in the ByrneWallace's Litigation & Dispute Resolution Team.

Mark specialises in advising national and international companies on business critical corporate disputes, and provides early stage strategic and tactical advices to companies with a view to minimising corporate risk during a dispute.Mark also has extensive experience advising clients in the state and semi-state sectors in relation to regulatory investigations and dealing with key stakeholders.

Reputation management is core to Mark's expertise and he has significant experience managing the corporate reputations of companies and high profile individuals during times of crisis.

Prior to joining ByrneWallace in October 2018, Mark worked in two other leading law firms in Ireland.

Key Experience

  • Successfully resolving a commercial court dispute between an Irish company and a Dutch company in the renewable energy sector.
  • Advising a large financial institution on a €20 million dispute with two insurers.
  • Representing a large domestic manufacturer on a multimillion euro contractual dispute with a Swedish company.
  • Advising a prominent sports person on a high profile contractual dispute before the Irish commercial court.
  • Advising a fintech company on a multimillion cross-jurisdictional contractual dispute.
  • Advising a national newspaper on its defence of over 30 High Court defamation proceedings.
  • Securing a court injunction against a national newspaper to prevent publication of details relating to a financial transaction involving a high profile businessman.
  • Advising a semi-state body on media queries and adverse publicity arising from a high profile incident.
  • Advising numerous national and international companies on protecting their corporate reputations both online and in the traditional media.
  • Acting for a high street retailer in two judicial review applications relating to its civil recovery programme.
  • Advising a regulatory authority on an investigation into a professional services firm.


  • Law and Accounting, University of Limerick, 2003
  • Admitted as a Solicitor, Law Society of Ireland, 2008
  • Commercial Diploma in Commercial Litigation, Law Society of Ireland, 2009
  • Professional Diploma in Arbitration, University College Dublin, 2010


  • Law Society of Ireland
  • Law Society of England and Wales
  • Dublin Solicitors Bar Association
  • Arbitration Ireland