At the end of the First World War in 1918, a Paris Peace Conference had been formulated by the Allies in 1919, being composed of four leading statesmen, viz. Loyed George representing Great Britain, M. Clemencean France, Signor Orlando Italy and President Wilson, the United States; and finally The League of Nations was founded in Geneva in January, 1920 and M.P. Hymans of Belgium was appointed the first President. The Aga Khan led the Indian delegates in Geneva, and attended the Disarmament Conference, where he delivered a stirring speech on February 19, 1932. He also attended the Third Disarmament Conference and made a speech on February 2, 1933. During the 15th session of the League of Nations, the Aga Khan also gave his speech to the assembly on September 27, 1934. He also addressed the League of Nations in Geneva during its 17th session on September 29, 1936. In sum, the Aga Khan's interest in international affairs in Geneva culminated in his election in the session of July, 1937 as the President of League of Nations in place of the former President, M.P. Van Zeeland of Belgium, and all the 49 votes cast in a secret ballot were found to be in his favour.
Aligarh was in special jubilant at the election of the Aga Khan as President of League of Nations. Dr. Ziauddin Ahmad, the then vice-chancellor remarked that it was a great honour to the Aligarh Muslim University, which owed much of its development and extension to the zealous efforts of the Aga Khan. He further said that towards making Aligarh the greatest Islamic centre of learning in the world, the Aga Khan had made a magnificent contribution. Writing about the Aga Khan III, Mushir Hosain Kidwai of Gadia, Bar-at-Law says: "In the League of Nations, in the presence of so many learned persons who claimed to represent nations scattered all over the world, but whose mentality was mostly materialistic, stood up a man - a responsible, thoroughly educated, well-experienced, well travelled, well polished man, a gentleman, a nobleman, respected by one and all, - and he proclaimed at the top of his voice that he was proud to belong to the Glorious Brotherhood of Islam. It was indeed thrilling. The bold announcement was thrilling. The occasion when it was made was thrilling. What a slap it was on the face of those cowards who felt shy at the name of Islam. The Aga Khan's words raised the prestige of Islam in an assembly which was almost prejudiced against it. `I was overjoyed. I am a man hard to bend before anybody - not even before a king. But I would gladly bow before a man who spoke from his heart those thrilling words.'"
The Aga Khan made his first presidential speech in the League of Nations on September 13, 1937 during its 18th session. Thus, Sir Samuel Hoare, the ex-Secretary of State of India was compelled to remark that, "The Aga Khan does not belong to one community or one country. He is a citizen of the world par excellence."
During the Second World War (1939-1945), the Aga Khan once again urged his followers to support the British cause in the war. The Aga Khan presided over the convocation of Aligarh University in 1938, and in its conclusion, he put his resignation from Pro-Vice Chancellorship in favour of Nawab of Rampur. The University was keen to have him associated, therefore, he was elected the Rector of the University. On June 16, 1945, the Aga Khan III presided over the first East African Muslim Public Workers Conference, and also held an historical Mission Conference of the Ismailis in Dar-es-Salaam.
On December 17, 1948, the Aga Khan III completed 65 years, 3 months and 9 days of his Imamate which is the longest record in the history of all the 48 Imams.
In 1949, the Aga Khan III was declared an Iranian citizen and was awarded the distinguished title of Hazratwala, i.e. His Royal Highness by His Imperial Majesty the Shahinshah of Iran. He also visited Pakistan for the first time after independence on February 2, 1950 and was awarded an honorary degree of LL.D. from the Dacca University in 1951. On March 3, 1951, the Syrian government invested him the title of Order of Ommayad. In 1951, the Aga Khan III paid his first visit to Iran to attend the marriage of the Iranian king with queen Sorayya. Arriving in Tehran, he looked up at the sky and the land-scape and exclaimed: "What a lovely and beautiful country I have. I had been cherishing for years the desire to visit my beloved native land." On February 11, 1951, one day before the wedding ceremony, His Majesty the King had awarded the Order of the Crown First Class to the Aga Khan. During his visit to Iran, he also went to see Mahallat. Thousands of people lined the roads for a glimpse of one whose ancestors had been the revered and benevolent rulers of the area.