[1] Born in Fond du Lac, Wisconsin, Jenison attended the public schools and the University of Wisconsin–Madison.

He engaged in newspaper work, from 1925 to 1937, and as a publisher, since 1938, of the Paris, Illinois Daily Beacon-News.

He served as lieutenant commander in the United States Navy, attached to the Deputy Chief of Naval Operations for Air, with service in the Pacific and Atlantic Forces, from April 1943 to September 1946.

[2] He resumed the publishing business,[2] and was named "master editor" by the Southern Illinois Editorial Association in 1986.

He was appointed to replace William D. Cox who was convicted in the United States District Court for mail fraud and filing a false income tax return.