As a military officer, Salvador Cienfuegos experienced the actions of the Mexican Army during the students' movement and the Mexican Dirty War. From 1 November 1967 to 15 December 1967, he served in the 6th Infantry Battalion in the Michoacán state and was the Section Commander. Later he served in the 3rd Infantry Battalion in Mexico City from 16 December 1967 to 31 August 1975 and was the commander of Company and Section departments.