Turner helped establish the interdisciplinary field that combines together cosmology and elementary particle physics to understand the origin and evolution of the Universe. His research focuses on the earliest moments of creation, and he has made contributions to inflationary cosmology, particle dark matter and structure formation, the theory of big bang nucleosynthesis, and the nature of dark energy.
He is a member of the National Academy of Sciences and a leading proponent of the theory of the origin of the universe known as the "Cold Dark Matter Theory." Turner chaired the National Research Council's Committee on the Physics of the Universe, which in 2003 published Connecting Quarks with the Cosmos. The report assessed the scientific opportunities that occur on the frontiers of research at the intersection of physics and astronomy. Turner completed a two-year term as assistant director for mathematical and physical sciences at the National Science Foundation in 2006.