He served in the RCN for nearly nine years during the Cold War years before leaving to attend university. Dr. Whelan completed his dissertation on treatment outcomes for military members with substance abuse and mental health issues and he went on to serve as clinical director for the CAF addiction treatment programs. In 2004, he established a private clinic for the treatment of complex military PTSD and developed a group therapy program for veterans to help foster peer support networks. He continues to conduct outcome-focussed clinical research, advocacy and outreach work, and he is active in several veterans organizations.