Paul has a background in particle physics. He became a Jesuit in 1995 and was ordained in 2004. He holds a PhD in astrophysics from the University of Paris (Saclay), joining the Vatican Observatory in 2010. He has been based in Tucson since 2011. He was named Vice Director in 2012, his main responsibility being the Vatican Advanced Technology Telescope (VATT). An overhaul of VATT's control system is due to be completed in June 2024. Paul teaches ASTR320 History and Philosophy of Astronomical Thought.