The month-long political impasse ended dramatically with Devendra Fadnavis returning as the chief minister again, backed by the Sharad Pawar-led NCP.
NCP leader Ajit Pawar was sworn-in as the deputy chief minister at Raj Bhavan.
Governor Bhagat Singh Koshyari administered the oath to the two in the morning ceremony, where only official media was present.
Prime Minister Narendra Modi on Saturday congratulated Devendra Fadnavis and Ajit Pawar for taking oath as chief minister and deputy chief minister of Maharashtra respectively.
In a tweet, he expressed confidence that the two will work for Maharashtra's development.
Congratulations to @Dev_Fadnavis Ji and @AjitPawarSpeaks Ji on taking oath as the CM and Deputy CM of Maharashtra respectively. I am confident they will work diligently for the bright future of Maharashtra.— Narendra Modi (@narendramodi) November 23, 2019
"People had given us a clear mandate, but Shiv Sena tried to ally with other parties after results, after which President's rule was imposed. Maharashtra needed a stable govt not a 'khichidi' govt," Fadnavis said.
Ajit Pawar, after taking oath as the deputy chief minister, said: "From result day on October 24, no party was able to form the government. Maharashtra was facing many problems, including farmers issues. So we decided to form a stable government."
The surprise swearing-in is being described as a political masterstroke of Sharad Pawar, who on Thursday night had said there was a consensus among the NCP, Congress and Shiv Sena that Uddhav Thackeray should lead the new government.