Hendrik Alexander Seyffardt was born in Breda on the 1st of November, 1872, as son of Louis William Seyffardt August, later Minister of War in the Van Tienhoven Government (1891-1894), and Catharina Louisa de Hollander. August Seyffardt was an officer in the Dutch army and during his ministry he steered a left-liberal course in which he pleaded for general training duty and a citizen army. His ideas were never realized, due to his poor relationship with Queen-Regent Emma.
According to good military tradition, Seyffardt enrolled as a cadet at the Royal Military Academy (KMA) in Breda at the age of fifteen. After his training, he was appointed second lieutenant at the Vestingartillerie (garrison artillery). In 1900, at the age of 28, he subsequently was appointed as a lecturer at the KMA (Royal Military Academy). Next to his teaching, he studied at the Hogere Krijgsschool (higher war college) in Haarlem in order to become qualified for a position within the General Staff. In 1928, as an interim step, he was appointed commander of the first division in the rank of Major General. A year later he was appointed Chief of the General Staff. One year later, in 1930, he was promoted to lieutenant general and in this rank he remained as chief of the General Staff until May 1934. In that month he retired, after a very meritorious career.
After his retirement, his fascist sympathies and his anti-communist ideas in particular became more clear. This became partly evident by his lectures for the highly authoritarian-conservative Verbond voor Nationaal Herstel (Alliance for National Recovery; VNH) led by Van Gybland Oosterhoff and from his articles in "Volk en Vaderland”, the magazine of the National Socialistische Beweging (national socialistic movement; NSB). During his speaking engagements for the VNH he aimed primarily on the pacifist movement (the “broken rifle") and he also pleaded for a stronger army. Furthermore, in 1935, for example, he also fiercely opposed against the then government's decision to join the sanctions against Italy, which had invaded Abyssinia.In 1937, Seyffardt was a member of the NSB for about half a year. Probably he decided to terminate his membership because of the struggles within the movement between Ir. Anton Mussert, "Leider der NSB” and Mr. Meinoud Rost of Tonningen, who preferred a more radical course for the NSB.
It is not clear how Seyffardt experienced the German invasion of the Netherlands. However, shortly after the capitulation he talked about "a changed understanding". Anyway, he was impressed by the German army and the plans of the German occupying forces.