Carlstrom is leading two cosmological research projects, the South Pole Telescope in Antarctica and the Sunyaev-Zeldovich Array at the Owens Valley Radio Observatory in California. Both projects are aimed at revealing new details regarding a mysterious phenomenon called dark energy, which makes the expansion of the universe accelerate. Carlstrom previously led experiments using the Degree Angular Scale Interferometer at the South Pole to make precise measurements of the cosmic microwave background radiation, the afterglow of the big bang. The DASI measurements have led to major discoveries in recent years that advanced modern cosmological theory.

His honors include a MacArthur Fellowship in 1998 and election to the National Academy of Sciences in 2002.