Rasmussen was born in Harrisburg, Pennsylvania. Following naval service in World War II, undergraduate education at Gettysburg College and graduate education at the Massachusetts Institute of Technology (MIT), he became a physics instructor at MIT in 1956.
Rasmussen received a professorship at MIT in 1958, and served in the Nuclear Engineering Department until 1994.
His initial research concentrated on investigating radiation and gamma rays. He was the head of the nuclear engineering department from 1975 to 1981. He headed the landmark Reactor Safety Study (WASH-1400) in the early 1970's. This student established the formal discipline of Probabilistic Risk Assessment (PRA), and for this he is known as the father of PRA and Probabilistic Safety Assessment (PSA). Among his numerous honors was his election to both the National Academy of Engineering (1977) and the National Academy of Sciences (1979), as well as serving a 6-year term on the National Science Board during the Reagan Administration. Professor Rasmussen won the Enrico Fermi Award for excellence in the field of nuclear energy in 1985 for his ‘pioneering contributions to nuclear energy in the development of probabilistic risk assessment techniques that have provided new insights and led to new developments in nuclear power plant safety. Perhaps his most remembered moment was his televised debate with activist Ralph Nader over the safety of nuclear power.