From 1984 until 1992, Pratt worked as an associate attorney for the Moss & Walton law firm in Indianapolis.

In 1997, Pratt became a judge in Marion County, Indiana, working in the Criminal Division and presiding over major felony matters from 1997 until 2008.

[1][2] In March 2009, Pratt expressed her interest in a federal judgeship to the staff of Indiana Senator Evan Bayh.

After interviewing with representatives from the United States Department of Justice and the Office of the White House Counsel, Pratt was nominated by President Barack Obama to the judgeship on January 20, 2010.

Pratt filled the vacancy that was created by Judge David F. Hamilton, who was elevated to the United States Court of Appeals for the Seventh Circuit.