In 1884 he was elected to the National Chamber of Deputies representing Entre Ríos. He served until May 1887, when President Miguel Juárez Celman appointed him as Mayor of Buenos Aires, then a newly federalized city. Crespo was only the Federal Capital's second mayor, succeeding Torcuato de Alvear.[2]
As mayor he oversaw a significant administrative milestone when the partidos of Flores and Belgrano were formally incorporated into the Federal Capital, dramatically expanding its territorial jurisdiction. This consolidation marked a pivotal moment in Buenos Aires' urban development as it transitioned toward becoming a modern metropolis.[2]
His administration engaged in a dispute with the Supreme Court, which ruled on the (at the time) controversial Avenida de Mayo project. The court mandated that expropriations would only apply to land directly required for the avenue's construction, rather than entire city blocks as originally planned. This judicial decision significantly impacted municipal finances, as the city government had intended to fund the project through subsequent sales of the fully expropriated properties. The ruling particularly benefited private landowners whose properties would front the new avenue, as their holdings appreciated in value.[4][5]
Among his most enduring contributions was the 1887 implementation of a standardized property numbering system, assigning one hundred numbers per city block (with odd numbers on one side and even on the other), a system that remains in use today. His administration also sold the original Teatro Colón to the Banco de la Nación Argentina, proposed construction of a new lyric theater at the current Congressional Palace site, surrounded by a grand plaza with four diagonal avenues, and prioritized wider avenues and new green spaces as public health measures to combat frequent epidemics.[4]
Due to health complications, he resigned as mayor in 1888 and was replaced, in interim fashion, by Guillermo Cranwell. The following year he was elected as a National Senator for Entre Ríos, marking his return to politics at the federal level.[6] His contributions to Buenos Aires were later commemorated through the naming of Villa Crespo, a neighborhood that honors his legacy.[7]
He died in Buenos Aires on 7 July 1893, a month after resigning from his seat in the Senate.[2]
