He served as the first mayor of Bacolod in 1938, as military governor of Negros and Siquijor Islands from 1942 to 1945, and as Secretary of National Defense and Interior under President Sergio Osmeña from 1945 to 1946.

Montelíbano was President of the Planters Products Inc., Chamber of Agriculture and Natural Resources of the Philippines; Board Chairman of Pacwood Inc. and Rizal Youth Development Foundation Inc. Country Bankers Insurance & Surety Co.; Country Bankers Life Insurance; Ferro-Cement Philippine Inc.; Philippine President lines and Modular Concrete Structures Inc. Chairman, Import Control Commission, 1951; Administrator, Office of Economic Coordination, 1954–1955; Chairman, National Economic Council, 1955–1956; and Chairman-General Manager, Rice and Corn Administration, 1968–1971.

Chairman-President of Capitol Subdivision Inc.; President, National Federation of Sugarcane Planters; and Senior Vice-President, Manila Electric Co.

He first married Corazón Unson Locsin whom which he has four sons and two daughters – Corazon, Ting, Alfredo Jr., Rudolfo, Roberto, and Oscar.

As distinguished economist and entrepreneur and as president of the Chamber of Agriculture & Natural resources, Bureau of Animal Industry, 1965; Good Citizenship Award, Community Chest of Greater Manila, 1962; 7.