Markus Burgstaller combines experience in public international law and EU law at the highest level of government with many years of experience in private practice. He acts for States, international organisations, businesses, and individuals in international disputes, mainly arbitrations under ICSID and UNCITRAL rules, and in proceedings before the Court of Justice of the European Union (CJEU).

Markus was lead counsel for the Slovak Republic in the Achmea case before the CJEU in which the CJEU ruled that EU law precludes a provision in an international agreement concluded between EU Member States that provides for investor-State arbitration. For his work Markus received the Financial Times Innovative Lawyers award for innovation in legal expertise – dispute resolution 2019, the award for "Most Important Decision" by Global Arbitration Review in 2018 and was named "Lawyer of the Week" by The Times in 2018.

Recognized as a leading individual in public international law in the UK (Legal 500, 2012 to 2018), Markus guest lectures at universities such as the University of Cambridge, the London School of Economics and Political Science, and Humboldt University in Berlin. He is nominated to the ICSID Panel of Conciliators by the Austrian Government. Markus is frequently interviewed and published in international media such as the Financial Times, The Economist, The Times, the BBC, and the Frankfurter Allgemeine Zeitung.