During 2020-21, Muller co-produced the critically acclaimed documentary film, The First Wave, with Director Matthew Heineman which chronicles the harrowing initial months of the COVID crisis in New York City.

Muller's professional career began in 2005 with the Maan News Agency in the Palestinian Territories where he worked as a reporter and editor covering events in the West Bank, East Jerusalem and the Gaza Strip including Israeli settlement construction, Israel's 2005 withdrawal from Gaza, and the 2006 Palestinian Legislative Council elections and the subsequent international boycott of the Hamas-led government.

He has since covered political and social issues in northern Uganda, Somalia, Sudan, Afghanistan, Democratic Republic of Congo and other conflict-affected areas.

[10] But over time, his interest broadened beyond violence and focused more on masculinity as a powerful social framework that affects nearly all aspects of how boys and men construct their lives and relationships.

[16] In 2011 his work on mobile military tribunals that aim to reduce mass rape in eastern Democratic Republic of Congo was included in the Open Society Foundations Moving Walls 19 Documentary Photography Exhibit.

“In an intellectual sense, I hope that it [the coverage] underscores the challenges of national identity and nation-states that exists in countless countries across the world and has, for centuries, been the source of immense bloodshed,” Muller told Time Magazine.

This collaboration culminated in an expansive exhibition at the Global Summit to End Sexual Violence in Conflict in London hosted by British Prime Minister William Hague and Angelina Jolie.