Teller played a leading role in the establishment of the Lawrence Livermore National Laboratory in California, intended as a rival to Los Alamos. He believed that competition would accelerate weapons development. This was a move done together with Ernest Lawrence.

Teller served as the director of the Lawrence Livermore National Laboratory, solidifying its role as a leading center for nuclear weapons research. He helped build a dedicated staff and provided leadership for projects.

Even after stepping down as director, Teller remained heavily involved with the Lawrence Livermore National Laboratory, serving as a consultant and continuing to influence its research agenda.