After graduating from Astoria High School in Astoria, Oregon, Dann began his engineering career surveying Fort Clatsop National Memorial in the Lewis and Clark Historic Park while serving as Assistant County Surveyor in Astoria (1950-1952). In 1952, Dann enlisted in the Army to serve in the Korean Conflict, where he reached the rank of Sergeant. He returned from Korea in 1954 to attend Oregon State University.
After a having his paperwork "lost" following an interview in 1967, Dann reconnected with and ultimately joined CH2M in 1968 in the Portland, OR, office.
After being diagnosed with Alzheimer's, he and his wife, Sally, dedicated much of their remaining years volunteering on Alzheimer's disease related projects. Both Dann and Sally were widely recognized for their efforts in bringing awareness to both the patient and caregiver of those afflicted with the disease.