He grew up with the background of his father's reform legislative service, but Miller said that he had not seriously considered running for office until after seeing the destructive aftermath of Hurricane Katrina in 2005:
I just felt that there was a lot missing in the way the state responded. We had a chance to really focus on what our priorities should be.... The best schools, the best jobs, the best communities are nothing if they're under ten feet of water.
During his campaign in 2011, Miller identified his top legislative priorities as fiscal accountability and job creation:
Persistent high unemployment has forced too many of our young residents to leave the state for decent job opportunities. Clearly, we must strengthen our efforts to promote economic opportunities. As your state representative, I'll go anywhere, meet with anyone, and never stop working to create high-paying jobs for our citizens.
Miller also said that improvements in drainage were essential on both the East and West banks of the Mississippi River. He cited the need for levees in St. Charles Parish strong enough to withstand hurricanes, in order to protect Montz and LaPlace. Miller also committed to stronger ethics laws. Miller won the seat vacated by Representative Gary Smith, Jr., a Democrat who was elected to the Louisiana State Senate. Miller defeated two opponents, one from each party: Republican Emile Garlepied, a former owner of a transportation company, and Democrat Ganesier "Ram" Ramchandran, a consulting engineer and a former member of the St. Charles Parish Council. In the nonpartisan blanket primary held on October 22, 2011, Miller failed by 110 votes to win the position outright. In the second round of balloting on November 19, Miller easily won with 5,201 votes to 3,143 for Democrat Ganesier Ramachandran. In 2013, Representative Miller voted to increase judicial pay, to repeal mandatory retirement ages for judges, and to lessen penalties for marijuana possession. He voted to forbid the state from enforcing federal firearms restrictions and to prevent the publication of the names of those with concealed weapon permits. Miller voted for surrogacy contracts for couples seeking another woman to bear their child. He also voted to bring state law in line with federal dictates on requirements of equal pay for equal work regardless of gender.
Opposition to Marriage and Conscience Act
On May 19, 2015, Miller was one of four Republicans on the House Civil Law and Procedure Committee—the others were Mike "Pete" Huval of Breaux Bridge, Nancy Landry of Lafayette, and Clay Schexnayder of Gonzales—who voted to table on a 10-2 vote the proposed Marriage and Conscience Act, authored by Republican Representative Mike Johnson of Bossier Parish and strongly supported by the conservativeLouisiana Family Forum. Only fellow Republican Ray Garofalo of Chalmette stood with Johnson. GovernorBobby Jindal, who supported the legislation, then issued an executive order to implement the measure. Johnson said that he will in 2016, if he is reelected, re-introduce the measure because he prefers a statutory law to address the issue. Johnson explained that the measure is designed to block the state government from pulling licenses or tax benefits from a company because of the owner's counter view of same-sex marriage. Among Democrats who opposed the measure were committee chairman Neil Abramson and Joseph Bouie, Jr., both of New Orleans, Patrick O. Jefferson of Arcadia, and Alfred C. Williams of Baton Rouge.