He was born at Mézin in the département of Lot-et-Garonne, France, where his father was clerk of the peace. He studied law and became an advocate at Nérac, beginning his public career there as municipal councillor (1868), afterwards mayor (1871), and as councillor-general of the département of Lot-et-Garonne (1871). Being an ardent Republican, he lost this position in May 1873 upon the fall of Thiers, but in February 1876 was elected deputy for Nérac. In the chamber he sat with the Republican Left, signed the protestation of May 18 1877, and was re-elected in October by his constituency.
In 1880 he became under-secretary of state in the department of the interior in the Jules Ferry ministry (May 1880 to November 1881). From August 7, 1882 to February 20, 1883 he was minister of the interior, and for a month (from January 29, 1883) was prime minister. His ministry had to face the question of the expulsion of the pretenders to the throne of France, owing to the proclamation by Jerome Napoleon Bonaparte (January 1883). Fallières, who was ill at the time, was not able to face the storm of opposition, and resigned when the senate rejected his project. In the following November, however, he was chosen as minister of public instruction by Jules Ferry, and carried out various reforms in the school system.
He resigned with the ministry in March 1885. Again becoming minister of the interior in Maurice Rouvier's cabinet in May 1887, he exchanged his portfolio in December for that of justice. He returned to the ministry of the interior in February 1889, and finally took the department of justice from March 1890 to February 1892. In June 1890 his département (Lot-et-Garonne) elected him to the senate by 417 votes to 23. There Fallières remained independent of party struggles, although maintaining his influence among the Republicans.
In March 1899 he was elected president of the senate, and retained that position until January 1906, when he was chosen by a union of the groups of the Left in both chambers as candidate for the presidency of the republic. He was elected on the first ballot by 449 votes againt 371 for his opponent, Paul Doumer.
| Preceded by: Charles Duclerc 1882-1883 | Prime Minister of France 1883 | Followed by: Jules Ferry 1883-1885 |
| Preceded by: Émile Loubet 1899-1906 | President of France 1906-1913 | Followed by: Raymond Poincaré 1913-1920 |