He joined the centrist Radical Civic Union (UCR), which at the time struggled under the system of "patriotic fraud" that kept the conservative Concordance government in power, as a member of their youth chapter, and in 1940, was elected to the Provincial Legislature.

Guzmán ran for and won the governor's post in Jujuy by a wide margin, and he promptly adopted the developmentalist policies advanced by the UCRI standard-bearer, President-elect Arturo Frondizi.

Some of the most important include the El Cadillal International Airport, a comprehensive housing plan, numerous clinics, the Children's and Neuropsychiatric Hospitals, provincial roads network, the International Bridge between La Quiaca and Villazón (Bolivia), new courts and provincial legislature buildings, the La Quiaca Normal School, pensions for teachers, and the province's first school of higher learning, the Institute of Economic Sciences (which became the National University of Jujuy in 1973).

[2] His policies, as well as his support for the refurbishment of numerous decaying churches in the mountainous province, earned him the appointment in 1960 as Knight Commander of the Order of St. Gregory the Great by Pope John XXIII.

[3] Guzmán subsequently founded the Jujuy Popular Movement (MPJ), though he would not return to office until January 1982, when the dictatorship of General Leopoldo Galtieri appointed him governor.