The 42-year-old Miller was sworn in by Indiana Supreme Court Justice Robert Rucker.
Miller is the newest member of the Indiana General Assembly and fills the Senate seat vacated by Indiana's new secretary of state, former Sen. Connie Lawson (R-Danville).
"Connie was extremely dedicated to serving Hoosiers in Putnam and Hendricks counties," Miller said. "I have some very big shoes to fill and welcome the challenge.
"As a resident and active member of the local community, I understand the issues facing central Indiana. There are great leaders in the Senate, and I will draw on their knowledge while using my experience as a father and public official to best serve my neighbors in the district."
Miller is the former Hendricks County Republican party chairman and currently serves as a member of the Indiana Republican State Committee and as the 4th District GOP chairman. A Purdue University graduate, he previously worked with the Indiana Office of Management and Budget.
Senate President Pro Tem David Long (R-Ft. Wayne) said Miller's expansive background will help make him a valuable leader on behalf of his district and the Indiana General Assembly.
"His broad experience, work ethic and passion for his community will help him represent Hoosiers in District 24 well," Long said.
Miller, a member of Avon United Methodist Church, has three children, Justin, Jessica and Brandon.