Brownback, who abandoned his presidential bid several weeks ago, announced his support for McCain during a campaign swing through Iowa, the McCain campaign said in a news release.
The campaign said Brownback will serve as a general co-chair of the campaign, and will lead the newly formed McCain Judicial Advisory Team.
"John McCain alone has the courage, leadership and character to lead our party to victory in 2008 while keeping faith with our most cherished values -- life, faith and family," Brownback said.
McCain said he was honored by Brownback's support, calling him a "man of faith and compassion whose integrity and unwavering commitment to protecting the dignity of human life, both born and unborn, has been an inspiration to me."
2014: The Year in Music [PHOTOS]