Mark Gieles obtained his PhD from Utrecht University in 2006, supervised by Henny Lamers and Simon Portegies Zwart. He then moved to the European Southern Observatory (ESO) in Chile as a research fellow and support astronomer on the Very Large Telescope (VLT). As part of the fellowship he spent a few month in Edinburgh working with Douglas Heggie. In 2009, he won a Royal Society University Research Fellowship (URF) which he took up at the Institute of Astronomy of the University of Cambridge and in 2013 he moved his URF to the University of Surrey, where he started a new astrophysics research group. From 2013 to 2019 he was PI of a Starting Grant of the European Research Council (ERC) and since 2017 he is an editorial board member of Monthly Notices of the Royal Astronomical Society (MNRAS), a leading journal in astronomy and astrophysics. In 2018, he became ICREA Professor at ICCUB, where he set up the Virgo gravitational wave group and where he now leads the stellar dynamics group.

My research focusses on trying to understand the formation and dynamical evolution of star clusters to shed light on the stellar initial mass function, black holes, gravitational waves, the globular cluster multiple population problem and the dark matter distribution in galaxies. The Milky Way contains approximately 150 globular clusters, for which we have exquisite observations. To interpret these, I use both star-by-star N-body simulations, fast approximate models for cluster evolution and dynamical mass models. I developed a family of mass models for star clusters (LIMEPY) to search for stellar-mass black holes in star clusters and to probe dark matter in the Milky Way using data from the ESA-Gaia satellite and related surveys. I make predictions for binary black hole mergers that formed dynamically in star clusters to understand gravitational wave sources. I am exploring the idea that extremely massive stars are the origin of "multiple populations" in globular clusters.