Federal Judge Sergio Torres will move from one high-profile position to another, after members of the Buenos Aires Provincial Supreme Court voted five to two to approve his appointment to the bench.
Torres' appointment, which passed the Senate on April 11, had been questioned on the grounds he does not formally live in Buenos Aires province.
His nomination, following the retirement of Justice Juan Carlos Hitters, enjoyed the support of Governor María Eugenía Vidal.
However, a judicial think-tank with ties to the ruling Cambiemos (Let's Change) coalition in the province, Usina de Justicia, opposed it, describing Torres as a "disciple" of former national Supreme Court Justice Raúl Zaffaroni.
"We cannot silence out opposition to said appointment, which we view as an enormous step backward in the fight we embarked on in Usina de Justicia to eradicate from the judicial system the abolitionist doctrine of his mentor Dr. Eugenio Zaffaroni", the group said in a statement in March.
Among other high-profile cases, Torres is known for having indicted former vice-president Amado Boudou on corruption charges.
Buenos Aires Province Supreme Court Justices Hilda Kogan, Luis Genoud, Héctor Negri and Daniel Soria voted in favour of Torres taking his oath, to join them at the province's highest court; while Chief Justice Eduardo De Lázzari and Justice Eduardo Pettigiani voted against it.
Torres is known for his support of witness protection mechanisms in Argentina's human rights trials.
The 12th Federal Court, which he presides, has led 964 investigations into drug trafficking since 2004, including 1,150 raids where more 23 million dosis of "paco" (cocaine paste) were seized, according to official court records.