Republican Gov. Phil Bryant will reportedly appoint state Agriculture Commissioner Cindy Hyde-Smith to the Senate on Wednesday.
The state was sued within hours of the bill signing.
The order blocks recent legislation that would have allowed people to refuse to provide wide-ranging services to same-sex couples by citing the religious grounds.
Phil Bryant, That Bigoted Anti-LGBT Mississippi Governor, Has Inspired a Band Called Fuck Phil Bryant
"If somebody tries to sue me, I'll just make another one about the First Amendment."
A bill that's supposedly designed to protect the religious freedom of people who disagree with homosexuality has been roundly criticized by LGBT advocates.
The law permits individuals, businesses, and religious organizations — including adoption agencies, hospitals, and schools — to refuse services to gay couples and transgender people.