Miller represented District 9A, which includes parts of Howard and Carroll counties.

[3] In 2006, Miller, along with fellow Republican Gail H. Bates, defeated David Leonard Osmundson to maintain his District 9A seat.

Shortly after college, Miller began to work as a Deputy Directory for the computer center at the White House Office of Presidential Personnel.

Later, he was appointed as the special assistant to the White House Liaison, Office of Administrator, Agency for International Development, a position he held from 1991-1992.

Miller has worked with fellow Republican Gail Bates to amended the Maryland Constitution to define marriage as the union between a man and a woman.