Marc represents major sports federations, clubs, athletes, agencies and other various sports stakeholders in front of decision-making bodies of international and national sports federations as well as in front of the Court of Arbitration for Sport and the Swiss Supreme Court. Marc's area of expertise encompasses all kind of compliance, disciplinary and ethics proceedings, contractual and financial, licensing or match manipulation matters. Marc regularly advises in the drafting of sports regulations and contracts, governance matters and in the implementation of decision-making, compliance and disciplinary processes within sports federations.

Before being known under its current  name Cavaliero & Cambreleng, the law firm founded by Marc was named Cavaliero & Associates (formerly known as Kleiner & Cavaliero). Prior to funding the law firm, Marc worked within the legal affairs division of FIFA for almost 10 years. As such, Marc acted as head of the disciplinary department between 2011 and 2017. In this role, Marc was responsible for all investigations into breaches of FIFA Regulations, infringements related to international transfer of players, match incidents, failure to comply with FIFA or CAS decisions (enforcement procedure), doping, match manipulation, third party ownership and other compliance and good governance issues. In addition, Marc also acted as Secretary to the FIFA Ethics Committee between 2011 and 2015 and was responsible for the supervision of all ethics-related proceedings. As such, Marc was responsible for the work of the three judicial bodies at FIFA and represented FIFA before CAS.

Between September 2008 and March 2011, Marc worked as Legal Counsel and Senior Group Leader in the FIFA Players' Status Department with a specialisation in dispute resolution. As such, Marc was in charge of handling all employment-related disputes, disputes related to solidarity contribution, training compensation and international transfers.

Marc holds a law degree from the University of Geneva and was admitted to the Geneva Bar in 2007. Marc also and graduated from the master’s programme in international sports law at the Higher Institute of Law and Economics (ISDE) in Madrid, Spain.

In addition to acting as lecturer on various sports law-related courses and master’s degree programmes, and for several football organisations, Marc frequently publishes academic articles on international sports law, including the regular publication of articles on decisions passed by the Swiss Federal Tribunal for Football Legal. He has also co-edited, with Professor Colucci, a comparative analysis of disciplinary procedures in football.

Marc is the Chairperson of the UCI Ethics Committee and Chief Ethics and Compliance Officer at World Aquatics. He was also appointed as Chairperson of the Elections Oversight Panel for the International Hockey Federation (FIH).