Jurors in York County deliberated for less than two hours before convicting 17-year-old Jacquez Brown of York in the July 2011 slaying of 19-year-old Anthony Wasilewski.
Police said Brown, then 15, shot the victim outside his home following an argument over a stolen cellphone. Authorities said he then forced his way into the home of an acquaintance, leading to a brief standoff.
Prosecutors said the victim was shot repeatedly in the back as he lay on the sidewalk.
Defense attorney Gary Kelley said his client "was scared and he was a kid ... attacked by a grown man."