Cain is a lifelong resident of Harris County. After graduating from Deer Park High School, he attended the University of Houston-Downtown.

While attending college, Briscoe began pursuing an interest in Republican politics and founded the College Republicans club. He earned his B.A. in communications in 2008.

Cain then attended South Texas College of Law. As a law student he founded a pro-life student organization and served as the President of the Federalist Society, a conservative group seeking reform to the American legal system. He earned his J.D. in 2012. 

In 2013, Cain started his own law firm. He also serves as legal counsel for Operation Rescue, an anti-abortion activist group, and as a board member for Right to Life Advocates, Inc. In 2015, Cain filed an amicus brief on behalf of a group of pastors arguing that a ruling striking down the state's school finance system should be upheld because the prevention of taxpayer dollars from going towards religious private school was "unconstitutionally inefficient."