Kumar, who was the first Chairman of Backward Classes Commission set up in 1997 and had also practised in Supreme Court and High Court, replaces C H Vijayashankar.
He was a faculty at the Havanur College of Law and is a Visiting Professor at the National Law School of India University based here.
Jayachandra also said Malikayya Guttedar, a six-time MLA and former minister, would serve as Pro-tem Speaker of the Assembly, which is meeting from May 29 for the first time after the Congress government came to power earlier this month.