He served in the 1986 Provincial Constitutional Convention as the body's Vice President, and secured the nomination as candidate for governor in 1987; he was defeated by the incumbent, Eduardo Angeloz of the UCR, by 5%, however.

The tragic death in 1989 of one of his daughters led to his divorce, and in December 1989, he married Olga Riutort, a San Juan Province Peronist lawmaker.

Defeated by Governor Angeloz by over 15%, this latter setback was significant because it cost De la Sota much of his support within the Justicialist Party (which was flush with victory in the 1991 mid-terms), leading to President Carlos Menem's endorsement of a separate party list in Córdoba for the 1993 mid-term elections, and to De la Sota's failure to regain a seat in Congress.

The director appointed to the office, Luis Juez, uncovered evidence of corruption by, among others, Córdoba Mayor Germán Kammerath, Public Works Minister Carlos Caserio, and the governor's chief of staff (and wife), Olga Riutort.

[6] He joined President Néstor Kirchner in supporting Vice-Governor Juan Schiaretti, who was elected in 2007 over Juez in highly contested results.

[9] Governor de la Sota distanced himself from the president following the 2011 elections amid a dispute over ANSES social security funds in excess of a billion pesos (USD 210 million),[10] and in September 2012 established a local Federal Peronist faction opposed to Kirchnerism.