In his role as the State's Attorney General between the years 1968-1975, Shamgar constructed and established a comprehensive infrastructure for the operation of the government and the civil service in compliance with the rule of law. The principles that he laid down, throughout his service, for the role of the legal advisors in the various branches of government continue to be, until today, the essential pillars for the legal advice within the public service.

​

Shamgar was appointed to serve as a justice in the Supreme Court in 1975, and he served as the President of the Supreme Court from 1983 until 1995.  During this term, Meir Shamgar exercised his role through many landmark cases and precedents in a wide variety of areas of the law that extended the body of the law and provided critical and comprehensive guidance on different topics. In his service in the Supreme Court, Shamgar strengthened the independence of the judiciary and defined its authority, he enhanced the protection of human rights and the principles of democracy and he supported the continued growth of the State of Israel. Some of the landmark decisions written by Shamgar have become the leading precedents upon which jurisprudence has continued to develop over the years. Furthermore, Shamgar pioneered and led the construction of the residence of the Supreme Court in Jerusalem, a building that represents the significance of the judiciary and its accessibility to the public.

​

Throughout the years, during his public service and after his retirement from the Supreme Court, Shamgar dedicated himself to contribution to the State of Israel in multiple avenues, including by heading major national investigation committees on major matters, such as the assassination of Prime Minister Rabin, the massacre in Hebron, the state responsibility for the consequences of underwater diving in the Kishon River, the appointment process of the Attorney General and the adoption of principles for negotiations for release of prisoners of war. Shamgar concluded in 2006, within the auspices of the Israel Democracy Institute, a complete and comprehensive proposal for the adoption of a constitution for the State of Israel.  He volunteered to serve as the head of many public organizations in the areas of education, Aliya, Jewish history, art, welfare and social aid. He was widely recognized in and outside of Israel for his achievements and he received many prizes and awards, including the Israel Award for special contribution to the people and the state of Israel.