[2] In 1846, Castro was pierced by a spear but Timoteo Aparicio managed to save his life due to their personal friendship.

Castro remained a prisoner of the Blancos and was sent to Entre Ríos where he joined the ranks of Justo José de Urquiza.

[2] When Venancio Flores began an uprising against President Bernardo Prudencio Berro on 1863, he invaded the country at the head of 250 men and was appointed Chief of Staff of the rebels.

After the success of the rebellion, he was the political chief of Salto and later participated in the Paraguayan War, where he obtained the rank of general.

[2][6] He supported the election of Lorenzo Latorre and he was appointed commander of the troops located south of the Negro River but his discrepancies with the dictator Máximo Santos separated him and he marched to Buenos Aires where he collaborated with the preparations for the Quebracho Revolution [es].