Madhya Pradesh Governor O P Kohli administered the oath of office to Gupta in a ceremony held at Raj Bhawan, which was among others attended by Chief Minister Shivraj Singh Chouhan.
The state government had appointed Gupta as Lokayukta two days ago.
The post of Madhya Pradesh Lokayukta had been lying vacant since June 2016 after the retirement of PP Naolekar, former Justice of Supreme Court.
Gupta was elevated to Madhya Pradesh High Court as Judge from lower judicial services in 2010.