The leaders of the League of Nations consisted of a Secretary-General, Deputy Secretary-General and a President of the Assembly selected from member states.
| No. | Portrait | Secretary General | Took office | Left office | Time in office | Country |
|---|---|---|---|---|---|---|
| 1 | Sir Eric Drummond (1876–1951) | 1 August 1920 | 2 July 1933 | 12 years, 336 days |  United Kingdom | |
| 2 | Joseph Avenol (1879–1952) | 3 July 1933 | 31 August 1940 | 7 years, 59 days |  France | |
| 3 | Seán Lester (1888–1959) | 31 August 1940 | 18 April 1946 | 5 years, 230 days |  Ireland |
| No. | Portrait | Name | Term | Country |
|---|---|---|---|---|
| 1 |  |
Jean Monnet | 1919–1923 | France
|
| 2 |  |
Joseph Avenol | 1923–1932 | France
|
| 3 |  |
Pablo de Azcárate | 1933–1936 |  Spain
|
 |
Massimo Pilotti |  Italy
| ||
| 4 |  |
Seán Lester | 1937–1940 | Ireland
|
| 5 | Francis Paul Walters | 1939-1940 | United Kingdom
|
| Nation | Name | Term |
|---|---|---|
 United States |
Raymond B. Fosdick | 1919 (provisional) |
| Italy |
Bernardo Attolico | 1919–1920 |
 Japan |
Nitobe Inazo | 1919–1926 |
| Italy |
Dionisio Anzilotti | 1920–1921 |
 Germany |
Albert Dufour-Feronce | 1927–1932 |
| Italy |
Giacomo Paulucci di Calboli | 1927–1932 |
| Japan |
Yotaro Sugimura | 1927–1933 |
| Germany |
Ernst Trendelenburg | 1932–1933 |
| United Kingdom |
Francis Paul Walters | 1933–1939 |
 Soviet Union |
Vladimir Sokoline | 1937–1939 |
 Argentina |
Luis Podestá Costa | 1938–1943 |
 Greece |
Thanassis Aghnides | 1939–1942 |
| Nation | Portrait | Name | Term |
|---|---|---|---|
| France
|
|
Léon Bourgeois | 1920 |
 Belgium
|
|
Paul Hymans 1st time |
1920–1921 |
 Netherlands
|
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|
Herman Adriaan van Karnebeek | 1921–1922 |
 Chile
|
|
Agustín Edwards | 1922–1923 |
 Cuba
|
|
Cosme de la Torriente y Peraza | 1923–1924 |
 Switzerland
|
|
Giuseppe Motta | 1924–1925 |
 Canada
|
|
Raoul Dandurand | 1925–1926 |
 Portugal
|
|
Afonso Costa | 1926 |
 Kingdom of Yugoslavia
|
|
Momčilo Ninčić | 1926–1927 |
 Uruguay
|
Alberto Guani | 1927–1928 | |
 Denmark
|
|
Herluf Zahle | 1928–1929 |
 El Salvador
|
.jpg)
|
José Gustavo Guerrero | 1929–1930 |
 Kingdom of Romania
|
.jpg)
|
Nicolae Titulescu | 1930–1932 |
| Belgium
|
|
Paul Hymans 2nd time |
1932–1933 |
 Union of South Africa
|
|
Charles Theodore Te Water | 1933–1934 |
 Sweden
|
|
Rickard Sandler | 1934 |
 Mexico
|
|
Francisco Castillo Nájera | 1934–1935 |
 Czechoslovakia
|
|
Edvard Beneš | 1935–1936 |
| Argentina
|
|
Carlos Saavedra Lamas | 1936–1937 |
 Turkey
|
|
Tevfik Rüştü Aras | 1937–1937 |
 British Raj
|
|
Sir Sultan Muhammed Shah, Aga Khan III | 1937–1938 |
| Ireland
|
|
Éamon de Valera | 1938–1939 |
 Norway
|
|
C. J. Hambro | 1939–1946 |
