 Guerrero served as one of the Vice Presidents in the administration of René Schick from May 1963 to August 1966 and became President of Nicaragua on 4 August 1966 following the death of Schick.Guerrero served the remainder of Schick's term and handed over the presidency to Anastasio Somoza Debayle on 1 May 1967, who in turn appointed Guerrero as his Foreign Minister.He was a relative of his predecessor René Schick.