The Cubs snapped a five-game losing streak thanks to Murphy's productive return to the majors.
This is Murphy's ninth year in the big leagues, but he has never played more than 52 games in any season. He had been with Iowa in Class AAA before having his contract purchased by the Cubs last Saturday.
He hit a home run in a loss to the Phillies on Tuesday and delivered a solo shot in the third inning of this game at tied it at 1-1.
Luis Garcia (0-1) walked the bases loaded in the ninth inning, although one of those runners was picked off for the second out of the inning. Murphy then came through with his home run to left-center off Justin De Fratus.
That gave the victory to Pedro Strop (2-4), who walked one and struck out the side in the eighth. Kevin Gregg turned in a perfect ninth for his 23rd save.