Congress leader Kamal Nath (72) was sworn in as the 18th Chief Minister of Madhya Pradesh in Bhopal on Monday.
Governor Anandiben Patel administered the oath of office to him.
On Friday, the Governor invited Mr. Nath to form a government.
The Congress on Thursday named Mr. Nath, the nine-time Lok Sabha member from Chhindwara, to head the State Congress Legislature Party, after hours of hectic parleys held by party president Rahul Gandhi with senior party leaders.
Mr. Nath, who has held several portfolios in the Union Cabinet, was appointed the Madhya Pradesh Congress Committee president on April 26 and was at the forefront in steering the party to a win in the November 28 Assembly polls.
The results were declared on December 11.
The Congress, which won 114 seats, has the support of one Samajwadi Party legislator, two Bahujan Samaj Party MLAs and four independents, to cross the majority mark of 116 seats in the 230-member Assembly.
The BJP, which ruled the State for 15 years, got 109 seats in this elections. Its Shivraj Singh Chouhan was the State’s longest serving Chief Minister since taking charge in 2005.