Despite his Swedish-speaking family background, Finnish language immersion was total in his youth, and he ultimately had to learn Swedish at school. Hägglund went to Svenska normallyceum i Helsingfors and was then educated not only at the Cadet School in Finland, but also attended the United States Army Command and General Staff College in Leavenworth, Kansas. He is also a fellow of Harvard University.
Despite his family's Swedish background, Hägglund experienced complete Finnish language immersion during his youth and had to learn Swedish at school. He studied at Svenska normalskolan i Helsingfors and the Cadet School in Finland, as well as the United States Army Command and General Staff College in Leavenworth, Kansas. Additionally, he is a fellow of Harvard University.