Among many other things Vieira was a civil servant in Macau prior to his governorship, being the Chief of General Staff of the Independent Territorial Command of Macau from 1973 to 1974 and Deputy Secretary for Public Works and Communications of the Government of Macau from 1974 to 1975. He then became Director of the Arm of Engineering of the Army from 1975 to 1976, Chief of General Staff of the Army and by inherency a Member of the Conselho da Revolução (Revolutionary Council) from 1976 to 1978 being the Captain of April who lasted more in Portuguese politics, with an extensive curriculum of public service. He was also made Honorary Director of the Arm of Engineering of the Portuguese Army.