Herbert David Cogley was born on December 28, 1945, in Brusett, Montana. He earned his high school diploma in Jordan, Montana, in 1964. In 1968, Cogley earned a BS in Mechanical Engineering Technology from Montana State University. The same year, he gained a commission as a second lieutenant in the U.S. Army Corps of Engineers through the Reserve Officers Training Corps at Montana State University.
Cogley was stationed in Vietnam for one year, beginning in late 1969, as an engineer with the 326th engineer battalion of the 101st Airborne Division. In November 1970, he was relieved from active duty, whereupon he returned to the United States. Cogley went on to receive a JD in law at the University of Montana Law School in 1975. He served on the legal staff of the Montana Legislature from 1975 to 1989. Since 1979, he has been owner and manager of Wildwood Log Homes in Clancy, Montana. Cogley has a wife, Helen, and a son.
From the guide to the H. David Cogley Papers, 1969-1970, (Maureen and Mike Mansfield Library Archives and Special Collections)