He worked as an interpreter in the Courts of First Instance of Abra and Ilocos Sur from 1886 to 1889 but was ordered banished to Benguet in 1890 by Spanish Governor-General Valeriano Weyler.

After the establishment of the First Philippine Republic, he was ordered by Apolinario Mabini to join the editorial staff of the official newspaper, El Heraldo de la Revolucion in Malolos from 1898 to 1899.

During the Philippine-American War, he served under the command of revolutionary General Manuel Tinio and became colonel of infantry.

[1] During his tenure in the legislature, Villamor lobbied for the separation of Abra into an independent province from Ilocos Sur, which was finally realized in 1917.

[6] During the Commonwealth era, he was appointed by President Manuel Quezon to head the Philippine Veterans Office.