Governor H R Bhardwaj administered the oath of office to Justice Chellur, who was the Acting Chief Justice of the High Court.
Chellur, who was appointed Judge of the Karnataka High Court in 2000, became Acting Chief Justice of the Kerala High Court last year.
Chief Minister Oommen Chandy, Assembly Speaker G Karthikeyan, Chief Secretary K Jayakumar, Ministers and High Court judges attended the function.