Guinn’s father was a career army officer, so the family lived in many parts of the US and in Germany. Guinn graduated from Frankfurt American High School in Frankfurt, Germany. He attended Rice University, graduating with a degree in Electrical Engineering. While at Rice, Guinn participated in the Army ROTC program and spent 28 years in the US Army Reserve, retiring with the rank of Lieutenant Colonel. Guinn worked for McDonnell Douglas at the NASA Johnson Space Center for 2 years on the space shuttle design team. He also worked as a computer software developer, computer consultant, and small business owner. Guinn was involved with the ColoradoCare Amendment 69 campaign in 2016 and served as the regional coordinator for southwest Colorado. He was, until recently, a co-chair for the Health Care and Senior Issues committee of Indivisible Durango. He was also elected to the Board of Directors for the La Plata Electric Association (LPEA) in 2017.