In early adulthood he served in the United States Air Force as a medic in London, England, and received an Honorable Discharge in 1962.

He was a founding member in 1991 of the Free Inquiry Group, Inc., (FIG) of Greater Cincinnati and Northern Kentucky and served as its vice president.

This led in 2003 to his authorship of a chapter in Kimberly Blaker's Fundamentals of Extremism: The Christian Right in America and in 2005 to his own book, Baubles of Blasphemy, a collection of some of his often irreverent essays and poetry.

In 2005, following ten successful years, he and his wife Helen retired from this venture, after transferring control and management of Camp Quest to other hands.

Kagin was also a founder and board member of Recover Resources Center, which provides an alternative addiction recovery program to the religiously oriented Alcoholics Anonymous.

As an outspoken public critic of religious intrusions into government, Kagin was a frequent speaker and debater at local and national events and has appeared on hundreds of radio and television programs, sparring on more than one occasion with Michael Medved.