Judge Hamilton was appointed United States District Judge for the Southern District of Indiana in 1994. Judge Hamilton previously was a partner at Barnes & Thornburg, a private law firm in Indianapolis. He served as Counsel to the Governor of Indiana from 1989 to 1991 and from 1984 to 1989 was an associate at Barnes & Thornburg.

Judge Hamilton grew up in Southern Indiana. He graduated from Haverford College in 1979 and Yale Law school in 1983. He also performed graduate work as a Fulbright Scholar at the University of Tuebingen in Germany. He served as law clerk to Judge Richard D. Cudahy on the United States Court of Appeals for the Seventh Circuit in Chicago and then returned to Indianapolis to practice law. He is a founding member of the Sagamore Inn of Court in the American Inns of Court. He served as a member of the Indiana State Recount Commission from 1986 to 1987 and as chairman of the Indiana State Ethics Commission from 1991 to 1994.