Thom Miller, from Mansfield in Ohio, found God during his time in prison and has been married to his wife, Belinda, 44, for almost eight years.
The 60-year-old pastor at United Christian Ministries International has married Reba, 19, but he says his congregation do not support his decision.
He runs a ministry which visits prisons and also has his own church in Mansfield.
Revd Miller admits that he does not have the full support of his congregation in Mansfield, but makes no secret of his alternative lifestyle.
According to The Independent, Thom and Belinda discussed the idea of adding another person to the family.
Mr Miller told Barcroft TV: "I don't preach about polygamy but I feel it is a very Christian lifestyle.
"I have no problem with homosexuals but I think it's wrong that their marriage is now recognised by the state, but my second marriage is not.
"I'm going to try and fight the bigotry of that.
"This is America and my wives and I have the right to live anyway we please, providing we're not hurting anybody."
Revd Miller knew Reba's family when she was a child and said that he and his wife bumped again into her while volunteering at the church as an adult.
Belinda Miller's said: "I wanted to have more of a family, I wanted to be complete, and having another lady in the house not only makes our family as a whole, but individually it's a beautiful thing because it's like having a sister around."
The denomination's website says it is dedicated to "promoting the cause of Jesus Christ through ministerial ordination, evangelistic crusades, multimedia presentations, Bible colleges, and missions world-wide."
The pair married at his church seven years after Thom married Belinda.
The pastor is now fighting for the state to acknowledge his marriage.
The trio have decided to raise the baby as a three.