Simon obtained his PhD in Mathematics from the University of Cambridge (2008). He then spent time as a post-doc in Montréal (2008-2010), IMPA (2010-2013) and Oxford (2013-2016). He is currently a professor (adjunto) at PUC-Rio University. Simon is one of the authors of the article "The chromatic thresholds of graphs" which recieved the Fulkerson prize, sponsored jointly by the Mathematical Optimization Society (MOS) and the American Mathematical Society (AMS), in 2018.

He researches in the areas of Combinatorics, Probability, Additive Number Theory and the interaction between these areas. In particular, his research focusses on: random graphs, random graph processes, Ramsey Theory and Noise Sensitivity.