[2] He had come as a boy with his family to California from elsewhere in New Spain with the De Anza Expedition in 1775.
Castro was a corporal in the artillery company of Presidio of San Francisco.
[3] The two made their home in San José and produced thirteen offspring between 1796 and 1824.
After serving as alcalde and in other public offices, Castro was granted Rancho San Pablo in 1823 by Governor Luís Antonio Argüello.
The land had previously been used for grazing cattle belonging to the Mission San Francisco de Asís, but was secularized by the new Mexican republic.