Justice Madan B Lokur was on Monday sworn in as a judge of the Supreme Court by Chief Justice SH Kapadia.
Prior to his elevation, Justice Lokur was Chief Justice of the Andhra Pradesh High Court.
With his elevation, the strength of the apex court has gone up to 26, five short of the sanctioned strength of 31 judges.
This is the first time that a judge, on his elevation to the apex court, was administered the oath during the summer vacation.
Justice Lokur, as Chief Justice of the Andhra Pradesh High Court, had headed the bench that quashed the 4.5 percent reservation in educational institutions and government jobs for Muslims within the existing reservation quota.