Caiado ran for president with the PSD, at 1989 Brazilian presidential election, obtaining 0.68% of the votes.
He was elected federal deputy for Goiás in 1990. The following year he joined PFL - now renamed DEM, to which he is still affiliated. He ran for governor of Goiás in 1994, obtaining 3rd place with 23.18% of the votes.[2]
Caido was re-elected federal deputy successively in 1998, 2002, 2006 and 2010. In 2014 he was elected Senator and from February 1, 2015 to January 1, 2019 has been the DEM bench leader in the Senate.
In the October 2018 elections Ronaldo Caiado ran for governor in the state of Goiás, next to his vice-candidate Lincoln Tejota. Reaching 1.773.185 votes (59,73% of the valid votes), he was elected in the first round, beating Daniel Vilela, from the Brazilian Democratic Movement (MDB), with 479.180 votes (16,14% of the valid votes).
A right wing politician, in his speeches Ronaldo Caiado often criticizes the current PT government. In 2014 he was elected senator for the state of Goiás with 1,283,665 votes.[3]