John Finley Yardley, son of an automobile agency sales manager, grew up in Saint Louis, Missouri. He graduated in aeronautical engineering from Iowa State College in 1944, and then served in the US Navy as an aircraft maintenance officer and engineer. He joined McDonnell in 1946, working in aircraft stress and structural analysis for the company' fighter designs of the 1950's. He was named as Project Engineer, Advanced Design, in 1958, with the objective of winning the Mercury manned capsule award. Yardley's team won the contract, and the follow-on Gemini program as well. Yardley served at McDonnell as the Mercury Spacecraft Project Engineer, 1959-1960; Mercury Launch Operations Manager 1960-1964; and Gemini Technical Director (1964-1968). John Glenn remembered Yardley as "…one of the real pioneers of the space program…working in his key spot there in industry to make sure that everything came off properly, with the emphasis on safety." Chris Kraft recalled that "…Yardley was always willing to come up with the next idea to overcome whatever problem we were having. You knew you would get not just the right answer from him, but the best answer. He was one of two outstanding program managers in the early days of human space flight."
After McDonnell-Douglas received the NASA contract for the Skylab space station, Yardley was named a Vice President-Deputy General Manager. He served as the company's Skylab Corporate-wide General Manager in 1968-1969. He was then assigned to head the unsuccessful McDonnell-Douglas bid for the Space Shuttle in 1969-1972.
In 1974-1981 he served as NASA's Associate Administrator for Manned Space Flight. He was responsible in this period for successful development of the shuttle through its first flight. After his death, NASA Administrator Dan Goldin recalled "…John Yardley was as responsible as any individual for getting the Space Shuttle program off the ground. He made STS-1 happen."
Yardley then returned to McDonnell Douglas as a Corporate Vice President and President of its Astronautics Company until his retirement in 1989.