Serrarens was born on 12 November 1888 in Dordrecht as the son of a bookkeeper of the department of Defense. In 1907 he became a teacher in Dordrecht, where he worked in that position until 1914. He then started studying law at Leiden University, but dropped out after two years. At the end of that year he was introduced to Catholic socialist movement Katholieke Sociale Actie, Serrarens joined the organization as a librarian. Until 1920 Serrarens moved throughout the circuit of Catholic socialist movements. After World War I devastated Europe, a sense of cooperation was felt in the countries of Western Europe. Serrarens was the negotiator between Belgian, German and French parties wishing to construct an internationally operating Roman Catholic labour union. His efforts were successful and Serrarens became Secretary General of the International Federation of Christian Trade Unions. During his tenure as Secretary General of the IFCTU Serrarens spoke out against the fascist regime of Italy and later the nazist regime of Germany. Between 1929 and 1937 Serrarens was member of the Dutch Senate. In the Senate he focused on the areas of education, social affairs, finances and foreign affairs. In 1937 he left the Senate to become member of the Dutch House of Representatives. In both houses he was member of the RKSP. When Germany invaded the Netherlands in 1940 the secretariat of the IFCTU was raided, Serrarens had however moved the most important documents of the organization to neutral Geneva, Switzerland in advance. In 1942 German police tried to arrest Serrarens at his home, Serrarens had however been tipped off and thereby escaped imprisonment. During the rest of the war Serrarens went into hiding. After the war ended Serrarens resumed his work for the IFCTU and showed himself a supporter of European integration. In 1945 the RKSP transformed into the KVP and in the House of Representatives Serrarens distinguished himself as the foreign affairs specialist of the KVP. On 19 March 1948 Serrarens together with Marinus van der Goes van Naters introduced a motion in the House of Representatives calling for more European integration, the motion passed. From 4 December 1952 until 6 October 1958 he was a judge at the European Court of Justice of the European Coal and Steel Community. To attain this position he left his occupation at the IFCTU and he resigned his seat in the House of Representatives. He was appointed as judge even though he had not completed any legal training. In 1958 he reached the mandatory age of retirement of 70. On 26 August 1963 Serrarens died in the Berg en Bosch hospital in Bilthoven.
