Born in Leeuwarden, one of his grandmothers was Jewish.[1] He trained as a journalist before taking employment with the liberalAlgemeen Handelsblad in 1903. Appointed foreign correspondent for the paper in 1908 he remained in this role until 1913 when he was given the role of Berlin correspondent.[2] Blokzijl settled in Berlin in 1918, working for the German press until 1940, while also serving as president of the Niederländischer Bund in Deutschland.[2]
Although based outside the Netherlands, Blokzijl, who had become a convinced Nazi, joined the National Socialist Movement in the Netherlands (NSB) in 1935.[2] He returned to his homeland following the German invasion and became the propaganda chief for the new NSB puppet regime.[2] In February 1941, the NSB forcibly replaced Hendrikus Colijn as editor of the Protestant newspaper De Standaard with Blokzijl, who held the title of General Secretary for Press Affairs for the party.[3] In fact Blokzijl's role was much greater than his title implied as he was actually effective head of the press in the Netherlands.[2] He also broadcast pro-Nazi shows on Radio Hilversum which were particularly noted for the strength of their anti-British sentiment.[2]
On 16 March 1946 Blokzijl became the first Dutch collaborator to be executed, dying at Scheveningen.[4]