Stationed in Cherry Point, North Carolina, Murphy served a six-month tour as a Staff Judge Advocate for the commanding officer aboard the USS Guadalcanal that deployed to the Mediterranean Sea and Mogadishu, Somalia, as part of the 22nd Marine Expeditionary Unit.
In February 2009, Murphy was appointed Chairman of the House Committee on Ways and Means, which is responsible for considering all legislation affecting the finances of the Commonwealth.
Murphy also played a key role in constructing the 2009 state budget, which contained historical increases for Chapter 70 education funding.
In 2007, Murphy was a candidate for the 4th Middlesex district State Senate seat vacated by Robert Havern III.
During the campaign, Murphy got into an argument in the House chamber with opponent and fellow Representative Patrick Natale.