Telangana and Andhra Pradesh Governor E.S.L. Narasimhan administered oath to him at a ceremony held at Raj Bhavan.
Chief Minister K. Chandrashekhar Rao, judges, lawyers and senior officials attended the ceremony.
Justice Radhakrishnan had been serving as the Chief Justice of the High Court of Judicature at Hyderabad for both the states of Telangana and Andhra Pradesh since July last year.
Narasimhan later left for Vijayawada to administer oath to Justice Praveen Kumar as the acting Chief Justice of Andhra Pradesh High Court.
With this, the separate high courts for Telugu states will become functional from Tuesday.
The High Court of Judicature at Hyderabad had been serving as common high court of the two states since June 2014 when Andhra Pradesh was bifurcated to carve out Telangana.
Last week, the Central government issued a notification for bifurcation of the High Court between the two states.
The gazette notification said January 1 would be the appointed day for the Andhra Pradesh High Court which will start functioning from Amaravati while the High Court of Judicature at Hyderabad will become the High Court for Telangana.
The employees and lawyers of Andhra Pradesh at the High Court of Judicature at Hyderabad on Monday reached Andhra Pradesh capital Amaravati.
The Supreme Court on Monday refused to take up for immediate hearing a petition filed by Andhra Pradesh Lawyers’ Association for postponing the shifting of High Court to Amaravati till the construction of High Court building was completed there.
The Supreme Court will take up the petition for hearing on Wednesday. The petitioners say that completion of High Court building could take about 10 months.