He will replace Anant Geete, the lone Sena minister in the previous Narendra Modi-led government, who lost from the Raigad Lok Sabha seat in last month's election, the leader said Wednesday.
Sawant, 68, who retained his seat by defeating Congress' Milind Deora by 1,00,067 votes, has been associated with the Shiv Sena since the party's early years.
He worked as an engineer with Mahanagar Telephone Network Ltd (MTNL) till 1995 and took voluntary retirement after he was nominated to the Maharashtra Legislative Council from governor's quota when Shiv Sena-BJP government came to power in 1995.
He was elected as MLC from the Mumbai Local bodies constituency. He contested the Lok Sabha election for the first time in 2014, defeating Deora, then an MP, from the Mumbai South seat by 1,28,564 votes.
Sawant is a deputy leader of the Shiv Sena, and also president of the MTNL trade union.