In 2000 Marnix started as lawyer at NautaDutilh, a large international law firm, where he specialised in Dutch employment law. Marnix was chairman of Nauta Dutilh’s works council for years.
In 2009, Marnix went in-house, joining Shell’s legal department as a corporate employment law counsel. Marnix worked on large restructurings within the Shell Group, with particular emphasis on expatriates.
Marnix completed the post-academic course in Dutch employment law (PALA).
In 2011, Marnix started Workx advocaten together with Maaike and Jochem. Marnix is a member of the Dutch Employment Lawyers’ Association (Vereniging Arbeidsrecht Advocaten Nederland) and the Amsterdam Employment Lawyers’ Association (Vereniging Arbeidsrecht Advocaten Amsterdam).