Nitish Kumar was on Monday sworn in as the Chief Minister of Bihar for the seventh time in two decades, in presence of top leaders of the NDA including Union Home minister Amit Shah and BJP national president Jagat Prakash Nadda.

Kumar, who heads the JD(U), was administered the oath of office at Raj Bhavan by Governor Phagu Chauhan, a day after he staked claim for the formation of a new government in the state, armed with unanimous support of all legislators of the NDA despite his party's plummeted tally.

The 69-year-old, who has had a continuous run since November, 2005, except for the period in 2014-15 when Jitan Ram Manjhi kept the chair warm for him, is on course to becoming the longest serving Chief Minister of the state, surpassing the record of Shrikrishna Singh who held the top post since before Independence till his death in 1961.

Amit Shah and J.P Nadda being welcomed by party workers in Patna on Monday. PTI

Kumar was first sworn in as CM in 2000, for a term that lasted barely a week as he failed to muster a majority and returned as a minister at the Centre in the Atal Bihari Vajpayee government.

Five years later, he returned with the JD(U)-BJP alliance winning a majority and upon completion of his tenure returned in 2010 when the coalition won a landslide victory in the assembly polls.

He stepped down in May, 2014, owning moral responsibility for the JD(U)s debacle in Lok Sabha polls, only to return in February, 2015 when a rebellious Manjhi was elbowed out.

In November, 2015, the assembly polls were fought and won by the Grand Alliance which then comprised JD(U), Lalu Prasads RJD and Congress with Kumar back as the Chief Minister.

He, however, abruptly exited the alliance in July, 2017, citing irreconcilable differences with the RJD and resigned as Chief Minister only to return in less than 24 hours armed with the support of the BJP.