Hemant Soren was administered oath by Governor Syed Ahmad. Two legislators - Rajendra Prasad Singh of Congress and Annapurna Devi of RJD - also took oath as ministers.
The swearing in ceremony took place at Birsa Mandap of Raj Bhawan.
The Bharatiya Janata Party (BJP) led government of Arjun Munda was dethroned after JMM withdrew support Jan 8. The present assembly period ends in December 2014 and this will be third government in the current assembly.
Hemant Soren has been given one week by the governor to seek trust vote and he is likely to seek trust vote July 16.
According to JMM sources, Hemant Soren will expand the cabinet after seeking the trust vote.
Before the swearing in ceremony Hemant Soren took blessings of his father Shibu Soren and mother Rupi Soren. No central leaders of the Congress attended the swearing in ceremony.