Former Intelligence Bureau officer RN Ravi was sworn in as the 20th governor of Nagaland at Raj Bhavan here on Thursday.
The acting chief justice of Gauhati High Court Arup Kumar Goswami administered the oath.
Chief Minister Neiphiu Rio and several legislators of the state government were also present at the event.
Ravi was earlier the interlocutor for the central government for the Centre-Naga peace talks.
Chief Minister Rio also took to Twitter to congratulate the new governor.
"Congratulations to Hon'ble Governor Shri RN Ravi on taking the oath of office. The oath was administered by Justice Arup Kumar Goswami, Chief Justice (Acting) Gauhati High Court. My best wishes to him in his term of office," Chief Minister Rio tweeted.