Irving Weissman received his B.S. from Montana State University in 1960 and an MD from Stanford University in 1965. During medical school he did research on thymus cell migration with James Gowans in 1964 at Oxford University, England. He was a postdoctoral fellow in Dr. H. S. Kaplan’s laboratory at Stanford University from 1965-1967, and was appointed as a Research Associate in the Department of Radiology upon completion of the fellowship. He was appointed Assistant Professor of Pathology, Stanford School of Medicine in 1969, Associate Professor in 1974, and Professor in 1990. He was an Investigator of the Howard Hughes Medical Institute from 1990-1992.
He was the Karel Beekhuis Professor of Cancer Biology from 1987 until 2005 and the Chair of the Immunology Program, a degree-granting program from 1986-2001. In 2002 he became Director of the Stanford Cancer/Stem Cell Institute, which was split into the Stanford Institute of Stem Cell Biology and Regenerative Medicine, and the Stanford Cancer Center in 2003; Weissman was Director of both, and was PI on the successful NCI Cancer Center grant. He stepped down as Cancer Center Director in 2008, but remains director of the Stem Cell Institute. In May 2005, he was named the Virginia and D. K. Ludwig Professor for Clinical Investigation in Cancer Research.