John worked as an engineer and structural detailer with the American Bridge Company in Pittsburgh, Pennsylvania, from 1947 to 1948. This experience increased his understanding of design practice but also encouraged him to gain construction experience. After teaching civil engineering at the University of Hawaii from 1948 to 1951, John spent one year as an engineer and estimator with Winston Brothers Company in Minneapolis, Minnesota. He then moved his family to Sacramento to work with Winston Brothers and the Al Johnson Construction Company as project engineer on the Nimbus Dam and Powerhouse Project from 1952 to 1955. His analysis of alternate construction methods during estimating and his design of temporary works during construction of this major infrastructure facility contributed significantly to the success of the project. Clark Oglesby, a professor of civil engineering at Stanford and also an eventual NAE member, brought one of his classes to the Nimbus project on a field trip. Clark was planning to develop a graduate construction program at Stanford and encouraged John to consider joining the faculty.
As a result, John became a professor of civil engineering at Stanford in 1955 and co-founded the Construction Engineering and Management Program with Clark Oglesby. He taught at Stanford for 35 years until retirement in 1990 and served as the first Charles A. Leavell Professor of Civil Engineering. His teaching focused on planning and construction engineering for large infrastructure projects. He later developed some of the first courses focusing on application of network planning techniques in construction. With Professor Oglesby, John also obtained research support from the Bureau of Yards and Docks, U.S. Navy, in 1958. Later renewed for a total duration of eight years, this pioneering support for research in construction eventually covered many critical topics: application of operations research techniques to construction operations, development of time-lapse motion picture techniques, application of engineering economics to policy decisions concerning construction equipment, and refinement of the critical path method of scheduling construction operations. John initiated research concerning the use of short-