Pakistan became an independent state in 1947. The first document that served as a constitution for Pakistan was the Government of India Act, 1935. The first Pakistani Constituent Assembly was elected in 1947 and after nine years adopted the first indigenous constitution, the short-lived Constitution of 1956. In October 1958, President Iskander Mirza abrogated the constitution. Shortly afterwards General Ayub Khan deposed Iskandar and declared himself president.
On 17 February 1960 Ayub Khan appointed a commission to report on the future political framework for the country. The Commission was headed by the former Chief Justice of Pakistan, Muhammad Shahabuddin, and had ten other members, five each from East Pakistan and West Pakistan, composed of retired judges, lawyers, industrialists and landlords. The report of the Constitution Commission was presented to President Ayub on 6 May 1961 (according to some writers report was presented on 29 April 1961)  and thoroughly examined by the President and his Cabinet. In January 1962, the Cabinet finally approved the text of the new constitution. It was promulgated by President Ayub on 1 March 1962 and finally came into effect on 8 June 1962. The Constitution contained 250 articles divided into twelve parts and three schedules. With the enforcement of this Constitution after 44 Months, Marshal Law came to end.
Pakistan was named as Republic of Pakistan. The constitution provided for a federal system with the principle of parity between East Pakistan and West Pakistan. Both the provinces would run their separate provincial governments. The responsibilities and authority of the centre and the provinces were clearly listed in the constitution. The central legislature had one house known as the National Assembly. There were 157 members of the National Assembly. The equality between the two wings were maintained in it.
The constitution provided for a presidential form of government, as opposed to the parliamentary form of government under the 1962 Constitution. The President, who had to be a Muslim not less than 35 years of age and qualified for election as a member of the National Assembly, was to be elected indirectly by an electoral college in accordance with the provisions outlined in the Constitution. The Electoral College formed by not less than 80,000 Basic Democrats, equally distributed between the two provinces. Under the Constitution of 1962, if the number of candidates for election to the office of President exceeded three, the Speaker of the National Assembly was to convene a joint session of the members of the National and Provincial Assemblies to select only three candidates for election, the remaining candidates then would not be eligible. This screening was not applicable to a person who was holding the office of the president, so if the sitting president was also a candidate the number of candidates would be four.
The term of the President was five years to act as Head of State as well as Chief Executive, solely responsible for country's administration. Governors and ministers were appointed and removed by him. He was eligible to promulgate Ordinances and veto against legislated laws only overrideable by two-thirds of the National Assembly. However, the president was not empowered to dissolve the Assembly except at the cost of his office also. On a charge of violating the Constitution or gross misconduct, the President might be impeached by the National Assembly for which one-third of the total members of the National Assembly must give written notice to the Speaker for the removal of the President. The President was to be removed from office if the resolution for impeachment was passed by votes of not less than three-fourths of the total members of the Assembly. A significant feature of the impeachment procedure was that if the resolution for removal of the President failed to obtain one-half of the total number of members of the National Assembly, the movers of the resolution would cease to be members of the Assembly.
There was no restriction of religion for a person holding the office of the Speaker of the National Assembly. Also, if the President resigned from his office or vote of no-confidence passes against him, according to the Constitution, the Speaker would act as the President of the State till the election of new President. Under these special circumstances, a non-Muslim might get the chance to be an acting President of Pakistan.
The Constitution of 1962 provided for elections of the central and Provincial legislatures for a term of five years. The members of the assemblies were elected by the Basic Democrats. The National Assembly was exclusively empowered to legislate for the central subjects. However, it could legislate on matters falling under provincial jurisdiction. The power to impose taxes was laid with the central legislature. The Assembly had to serve as a court in the cases of impeachment or conviction or to declare the President as incapacitated. It could amend the Constitution with a two-thirds majority. However, if the president's veto was overridden, he had the right to ask for the assent of the Electoral College. The procedure of the provincial assemblies was identical with that of the National Assembly.
Urdu and Bengali were recognised as national languages.
1) Written Constitution The Constitution of 1962 was a written document. It consisted of five schedules and 250 articles.
2) Rigid Constitution . A rigid constitution can only be amended through a particular process. If an amendment to the constitution is passed by at least two-third majority of the parliament then it becomes a part of law after authentication by the President.
3) Federal System A federal system was introduced in the country. It consisted of a central government and two provincial government comprising East and West Pakistan.
4) Presidential form of Government President was the head Executive of the nation. He was empowered to nominate the ministers of his cabinet.
5) Unicameral Legislature
6) Indirect Method of Election The President was elected by an Electoral College comprising 80,000 Basic Democrats, equally distributed between the two provinces.
7) Provincial Governments There were two provincial governments. Each of them was headed by a governor. He enjoyed powers in the province which the President enjoyed in the center. The Governor was empowered to appoint provincial ministers with the sanction of the President of Pakistan.
8) Provincial Legislature Each province was provided with a legislature. It originally consisted of 150 members. However, later on this number was increased to 218.
9) Powers of President According to the 1962 Constitution the President should be a Muslim with the term of 5 years. He was eligible to promulgate Ordinances and veto against legislated laws only override-able by two/thirds of the National Assembly. However, the President was not empowered to dissolve the Assembly except the cost of his office also.
10) Restrictions to the President The President was not allowed to hold any office of profit in the service of Pakistan but was not prevented from holding a managing private property.
11) Islamic Law No Law would be passed against the teaching of Quran and Sunnah and the existing laws would be made Islamic in character.
12) Fundamental Rights The constitution of 1962 laid down fundamental rights of speech and expression, freedom to choose profession and freedom to profess religion. With Regards to civil rights, familiar right such as the rights of life, livery and property were granted.
13) Role of Judiciary The Judiciary was responsible for the interpretation of laws and executive orders in the light of the principles embodied in a written constitution.
14) Supreme Judicial Council A supreme judicial council consisting of two judges of supreme court chief justice of supreme court and two judges of high courts was to be established.
The second martial law was imposed on 26 March 1969, when President Ayub Khan abrogated the Constitution of 1962 and handed over power to the Army Commander-in-Chief, General Agha Mohammad Yahya Khan. On assuming the presidency, General Yahya Khan acceded to popular demands by abolishing the one-unit system in West Pakistan and ordered general elections on the principle of one man one vote.