Politician and journalist. He was a member of the Democratic Party, Mayor of Madrid, President of the Congress of Deputies and Secretary of the Interior.

Nicolás María Rivero is of modest origins. He nevertheless studied Medicine at the University in Seville and one of his professors, named Hoyos, helped him find a position as clerk at the Council. In 1834, he helped in the fight against cholera. He decided to dedicate himself to law and journalism instead of medicine and started to study law. He was friends with Fernando de Castro, Federico Rubio and Gali, Manuel Cantero, and started a career in politics.

In 1845 he decided to live in Madrid, he collaborated with El Siglo and was elected representative to the Spanish parliament in 1847. After the revolution on 1848, he became a radical democratic politician. He signed the manifesto of the democratic party on April 6, 1849, along with other politicians such as Aguilar, Ordax Avecilla, Aniceto Puig. The manifesto defended individual rights, political, economic and social principles.

After the 1854 Revolution, Rivero became briefly governor of Valladolid.

Nicolás María Rivero founded La Discusión, the most important democratic journal at that time, with the help of Orense, Figueras, and Pi i Margall. The most importance democratic politicians published in this journal.

He was particularly opposed to the presence of European countries such as Spain and France in Africa.

Rivero participated to some conspiracies against the Queen Isabel II in Madrid, prior to the 1868 Gloriosa Revolution. He was instrumental in the first days of the Revolution. He became then mayor of Madrid. In the 1869 government elections, he joined Prim (they won 7 seats) in a list of candidates that defended a democratic monarchy.

He went into temporary exile to France in June 1873.