Governor D Y Patil, who administered the oath to Manjhi, handpicked by outgoing CM Nitish Kumar, and 17 ministers at a function at Raj Bhawan, directed the new government to seek a trust vote on the floor of the House on May 23.
The new Cabinet comprised all ministers of the Nitish Kumar government.
Vijay Chaudhary was the first to take oath after Manjhi. Vijendra Prasad Yadav, Narendra Singh, Brishen Patel, Ramai Ram and Bhim Singh followed.
Two Independents Dulal Chand Goswami and Binay Bihari were rewarded for supporting the government after it became a minority following parting of ways with the BJP.
Prime Minister-elect Narendra Modi tweeted "Congratulations to Shri Jitan Ram Manjhi on taking over as Bihar Chief Minister ... I wish him the very best and assure our support in development of Bihar."
Emerging from nearly 45-minute swearing in ceremony, Manjhi told reporters that he would seek a trust vote of his government on May 23 and expand his cabinet thereafter.