His experience and success as a key senior manager in the operations sides of Ford Motor Company and then General Motors led the Franklin Roosevelt administration to commission him directly as a lieutenant general in the United States Army to help lead the United States' war materiel production efforts for World War II.

[7] Knudsen worked for Ford from 1911[8] to 1921,[9] a decade that saw the formative development of the modern assembly line and true mass production.

Knudsen was appointed as Chairman of the Office of Production Management and member of the National Defense Advisory Commission for which he received a salary of $1 per year.

In both positions, Knudsen used his extensive experience in manufacturing and industry respect to facilitate the largest production job in history.

Knudsen's influence not only smoothed government procurement procedures but also led companies that had never produced military hardware to enter the market.

"[17][18][19] He was appointed Director of the Air Technical Service Command when it was founded in July 1944 at Patterson Field, Ohio.

[21] They had three daughters, Clara, Martha, and Elna, and one son, Semon "Bunkie" Knudsen, who also became a prominent automobile industry executive.

This article incorporates public domain material from Lieutenant General William Signius Knudsen official U.S. Air Force biography.