Born in England, Plesner grew up in Jerusalem and served as an officer with the Sayeret Matkal elite unit during his national service in the Israel Defense Forces between 1989 and 1994. He went on to study at the prestigious Amirim Program of Excellence at the Hebrew University of Jerusalem, where he gained a BA with distinction in economics. Plesner then spent several years in the business world, first as a consultant to major financial corporations in the UK, and then as co-founder and manager of an international software company. He moved on to the John F. Kennedy School of Government at Harvard University, where he gained an MA in political economics and security studies, and spoke regularly on behalf of Israel. Upon his return to Israel, Mr. Plesner assumed the position of Head of Special Projects in the Prime Minister's Office under then-PM Ariel Sharon. When the Kadima Party was founded in early 2006, Mr. Plesner was appointed the first Secretary-General of the nascent party, and led the formation of its organizational infrastructure. A Member of Knesset since 2007, Plesner is Deputy Chairman of the Kadima Faction and a member of both the Constitution, Law and Justice Committee and of the Defense and Foreign Relations Committee. Plesner founded the European Forum of the Knesset, a parliamentary group dedicated to improving relations between the Knesset and European legislators, and chairs the Knesset's permanent delegation to the Council of Europe. During his time in the Knesset, Plesner has spoken out on issues ranging from national security and electoral reform to preservation of the environment and excellence in education.