Patricio Rivas, a wealthy Nicaraguan lawyer, was Acting President (then called Supreme Director) of Nicaragua from June 30, 1839 to July 27, 1839 and from September 21, 1840 to March 4, 1841. Later he served as a President of one of the several competing governments of Nicaragua from October 30, 1855 to June 24, 1857. However, he was merely a puppet president; rule was held by William Walker. He belonged to the Democratic Party (Liberal Party).
Rivas provisionally occupied the Presidency of the Republic of this Central American country during the worst period of the National War of Nicaragua, between October 25, 1855 and June 24, 1857. He had to face the parallel governments of the entreguista Fermín Ferrer (legitimist) and the usurper William Walker (filibuster).
He briefly served as interim Supreme Director of the State of Nicaragua from June 30 to July 27, 1839, before being popularly elected as Supreme Director, a position he held from September 21, 1840 to March 4, 1841 .
In 1855, Patricio Rivas was appointed Provisional President as a result of an agreement signed in Granada between the Legitimist General Ponciano Corral and the filibuster William Walker, de facto head of the democratic side. This agreement was rejected by the legitimist José María Estrada who was the Acting President.
Rivas had the support of Walker at the beginning of his government. Due to the patriotic attitude of the government of the Costa Rican President Juan Rafael Mora Porras against the presence of the filibusters in Nicaragua, the government of Rivas declared war on Costa Rica in early 1856, invading Guanacaste. However, the Costa Ricans commanded by Juan Rafael Mora, defeated the filibusters in the battle of Santa Rosa and the Second Battle of Rivas (not to be confused with the First Battle of June 29, 1855, and in which Enmauelle Mongalo had a role heroic to burn the Mesón de Máximo Espinoza).
The candidacies of Rivas, Máximo Jerez and Trinidad Salazar were presented at convened elections to elect a new President. None obtained an absolute majority and it seemed that Congress was going to choose Jerez. However, Walker wanted to be called new elections. Rivas, eager to get rid of the tutelage of the filibuster, moved from Granada to León, where Walker arrived in June 1856, still in apparent cordiality. But, when Walker left, Rivas moved the government to Chinandega and repealed his decree calling for elections. Walker then announced in Granada the deposition of Rivas and his replacement by the proxy government of Fermín Ferrer.
Rivas declared Walker a traitor in Nicaragua, and remained at the head of the government in the western region of the country, where the armies of Guatemala and El Salvador arrived shortly after, attacking the cities of Granada and Masaya. For its part, the Costa Rican army expelled the filibusters from the San Juan river basin.
Walker capitulated on May 1, 1857. Shortly thereafter, on June 24, a triumvirate took office, composed of Máximo Jerez and Tomás Martínez Guerrero, which ended the turbulent government of Patricio Rivas.
Rivas was popularly known with the nickname of "Patas Arribas."