The term systems engineering dates back to Bell Telephone Laboratories in the early 1940s [Schlager, 1956; Hall, 1962; Fagen, 1978]. Fagen  traces the concepts of systems engineering within Bell Labs back to early 1900s and describes major applications of systems engineering during World War II. Hall  asserts that the first attempt to teach systems engineering as we know it today came in 1950 at MIT by Mr. Gilman, Director of Systems Engineering at Bell.
Hall  defined systems engineering as a function with five phases: (1) system studies or program planning; (2) exploratory planning, which includes problem definition, selecting objectives, systems synthesis, systems analysis, selecting the best system, and communicating the results; (3) development planning, which repeats phase 2 in more detail; (4) studies during development, which includes the development of parts of the system and the integration and testing of these parts; and (5) current engineering, which is what takes place while the system is operational and being refined.
The RAND Corporation was founded in 1946 by the United States Air Force and created systems analysis , which is certainly an important part of systems engineering.
The Department of Defense entered the world of systems engineering in the late 1940s with the initial development of missiles and missile-defense systems [Goode and Machol, 1957].
Paul Fitts addressed the allocation of the systems functions to the physical elements of the system in the late 1940s and early 1950s [Fitts, 1951].