On 18 December 1875, he was elected to the Swiss Federal Council and handed over office on 31 December 1892. He was affiliated to the Free Democratic Party of Switzerland. He was elected President of Switzerland  in 1881 and 1887.
During his office time he held the following departments:
- Department of Home Affairs (1876–1878)
- Department of Trade and Agriculture (1879–1880)
- Political Department as President of the Confederation (1881)
- Department of Trade and Agriculture (1882–1886)
- Political Department as President of the Confederation (1887)
- Department of Foreign Affairs (1888–1892)
He died in Bern in 1899.
Droz has been described as a "man of progress" and "one of Switzerland's major political figures". He was a radical democrat who clashed with Bismarck over a police spying case  , the Wohlgemut Affair, in 1889.
In La Chaux-de-Fonds a street (rue Numa-Droz, the longest in the town) and in Neuchâtel a square (place Numa-Droz) are named after him. A statue by Charles l'Eplattenier which was erected by the station is at present being renovated and will be placed on Rue Numa-Droz in the autumn of 2012.
- Numa Droz, Souvenirs d'un vieux montagnard. Histoire d'un proscrit de 1793. Nouvelle neuchâteloise, La Chaux-de-Fonds, Imprimerie du National suisse, 1869
- Numa Droz, Instruction civique : manuel à l'usage des écoles primaires supérieures, des écoles secondaires, des écoles complémentaires et des jeunes citoyens, Lausanne, D. Lebet, 1884
- Numa Droz, Études et portraits politiques, C. Eggimann (Genève), F. Alcan (Paris), 1895
- Numa Droz, Le rachat des chemins de fer suisses, Bâle et Genève, Georg, 1898
- Numa Droz, Essais économiques, Genève, C. Eggimann, 1906