23-year-old Gerald Shaffer Jr. is to be sentenced March 8.
Prosecutors said 54-year-old Mark Wallace crossed the street in front of an SUV driven by the defendant's father, Gerard Shaffer Sr., and was thrown to the ground in the ensuing April 2010 fight with both men. Shaffer's father, a Philadelphia firefighter, was also charged but died in 2011.
Defense attorney Coley Reynolds said his client was trying to stop the fight, and jurors apparently concluded Monday that Shaffer didn't intend to hurt Wallace. Assistant District Attorney Peter Lim says jurors apparently decided on a verdict "in the middle" between a murder conviction and acquittal.