Murphy is introduced as a criminal, but is actually far from being a bad person. He even shows benevolence and nobility in certain situations in the game, like when he tries to dissuade J.P. Sater from committing suicide or saving Anne Cunningham from falling off a cliff, despite her being his enemy.
He tries to avoid hurting anyone unless he really has to. But there is also a darker side to his personality, as he sometimes exhibits a short temper and seems to feel a great deal of self-loathing and pain over the death of his son.
Murphy repeatedly talks out loud to himself when analyzing a situation or just comments on the events, probably to compensate for the loneliness.
But still many aspects of his personality remain ambiguous, as his character is formed by the players' decisions regarding his ethics and morality.
Prior to the events of Downpour, Murphy was a family man; husband to Carol Pendleton and father to Charlie Pendleton. Murphy and Charlie enjoyed playing ball, flying kites and working on cars.
Charlie was abducted by the Pendleton's neighbor Patrick Napier. Napier, a (later) convicted pedophile and murderer, stuffed Charlie into a canvas sack which he then threw into a lake. Charlie's death and its ensuing emotional toll on both parents dissolved the marriage. By the time of Murphy's incarceration in Ryall State Penitentiary, Carol harbors a bitter resentment towards Murphy evidenced by obtainable letters between the two.
Overwhelmed by the desire for revenge, Murphy hijacked a police patrol car and proceed to evade arrest for 10 hours on purpose. This marked the end of his marriage, but brought him one step closer to Napier.
In prison, Murphy strikes a deal with dirty corrections officer George Sewell arranging an "unsupervised" meeting between the two in the prison showers. Murphy violently attacks Napier with his fists and with weapons left behind by Sewell. Depending on player choices during the game Murphy is revealed to have either killed Napier during the confrontation or to have beat him to the edge of death forcing Sewell to come in and finish the job.
He is voiced by David Boyd Konrad.
Murphy's name is a homage to fictional character Randle McMurphy in the novel One Flew Over the Cuckoo's Nest.