GOP presidential hopeful Marco Rubio hired Eric Teetsel to work on his campaign in order to aggressively reach out to evangelicals.

Teetsel is the executive director of the Manhattan Declaration, a "call of Christian conscience" on life, marriage and religious liberty. Numerous faith leaders founded the Declaration in 2009, including Robby George and the late Chuck Colson, and more than 550,000 believers have signed.

Teetsel worked at the American Enterprise Institute (AEI) prior to his position at the Manhattan Declaration. During his time at AEI, he helped to build and launch the Values and Capitalism project.

The evangelical is known for being a youthful Christian, who respects past contributions while focusing on the future and forgiving past grievances. Many evangelicals trust him because of his strong stance on marriage. Back in 2013, Teetsel was featured in a New York Times article titled "Young Opponents of Gay Marriage Undaunted by Battle Ahead." In the article, he was identified as a member of the "pro-marriage" movement.

Back in April, the young conservative also made public comments following the Q conference, an event that focused on pressing issues facing religious faith. Nearly 1,300 Christian leaders attended the event in Boston at a Baptist Church where pro-gay and anti-gay speakers came together to talk about America's and Christianity's views on sexuality.

"The aim of Q is to create space for learning and conversation, and we think the best way to do that is exposure," Q founder Gabe Lyons said at the time. "These are conversations that most of America is having, and they are not going away."

Yet, Teetsel strongly disagreed with Lyons' views and urged him to rescind his invitations to pro-gay panelists. Teetsel called them "false prophets professing to be Christians."