Hamilton has been active in Log Cabin for over twenty years serving as President of Log Cabin Los Angeles and Chairman of California Log Cabin. He has served on the national board of Log Cabin Republicans since 2004.

An educator since 1972, he teaches sixth grade in the Duarte Unified School District. He met his life partner, John Ruble while touring the world as a performer with the Musical Americans in 1970. Terry and John became official domestic partners in the state of California in 2005.

Hamilton earned an MA in Educational Management from the University of La Verne and a BA in Psychology from Point Loma Nazarene University.