Murphy was born in Moncton, New Brunswick. His family has produced a multitude of politicians, including his cousin Mike Murphy, the former Liberal MLA of Moncton North. Murphy was elected mayor in 1998, defeating the incumbent, and was acclaimed for re-election in 2001. He did not contest the 2004 municipal election. He was first elected to parliament in the 39th Canadian federal election where he succeeded Claudette Bradshaw. Prior to being elected mayor, he served on city council from 1992 to 1998.