Herschbach, who was born in San José, California, was educated at the University of Stanford and at Harvard University, where he gained his PhD in 1958. After teaching at the University of California, Berkeley for four years, he returned to Harvard in 1963 as professor of chemistry.

Herschbach has worked on the details of chemical reactions; for example, a simple reaction in which potassium atoms and iodomethane molecules form potassium iodide and methyl radicals as products, that is: K + CH₃I → KI + CH₃∙

He decided to use molecular beams to examine the nature of the reaction. The reagent molecules were formed into two collimated beams at a sufficiently low pressure to make collisions within the beams a negligible event. The beams were allowed to collide and the direction and velocity of the product molecules measured.

Herschbach was able to draw some conclusions about the reaction. He demonstrated, for example, that the reagents would only react if the incoming potassium atoms struck the iodomethane molecules at the iodide end. As techniques were refined and extended Herschbach demonstrated that the study of molecular beams could throw considerable light on reaction dynamics. For his work in this field he shared the 1986 Nobel Prize for chemistry with the American chemist Yuan Lee (1936– ) and John Polanyi.