He received his Ph.D. in 1988 and then completed a two-year Postdoctoral Research Associate at York University in Toronto, Ontario, Canada.
In April 1992, he launched the OGLE project, which aims at finding extrasolar planets using gravitational microlensing technique.
He was a pioneer of the use of gravitational microlensing which enabled him to exclude the presence of dark matter in the form of regular low-luminosity astrophysical bodies in the Milky Way halo.
OGLE made many important contributions to the studies of the structure of the Milky Way and neighboring galaxies and calibration of the cosmic distance scale.
In 2020, astronomers from the University of Warsaw’s OGLE team at the Astronomical Observatory discovered the smallest rogue planet in the Milky Way galaxy thus confirming that low-mass rogue planets are common in the Milky Way, that there may be billions of them, and that they can be detected and characterized by observations from the Earth's surface.