After two full days of deliberations, the jury found 20-year-old Derrick Williams guilty of first-degree murder and attempted murder, along with gun and gang allegations.
Co-defendants Darnell Houston and Lamar McKnight were convicted Friday by a separate jury panel. Both face possible life in prison.
On Dec. 25, 2010, Kashmier James was shot and killed in the 1700 block of W. 85th Street in Manchester Square. James' daughter, Neveah, was sitting in the front seat of the family car when she was killed, prosecutors said.
Houston, 38, and McKnight, 28, were later arrested for James' murder. Police believe the gang members were out looking for rivals and Houston mistook James' friend for a gang member on the night of the shooting.
Ezekiel Simon, 20, was also involved in the murder. Simon was awaiting sentencing and faces 29 years in state prison.
Williams, who was a backseat passenger the night of the shooting, faces a maximum sentence of 50 years to life, according to Deputy District Attorney Antonella Nistorescu.
He is not eligible for life without the possibility of parole because he was 15 at the time of the crime.
Williams, Houston and McKnight are scheduled to be sentenced on Sept. 16. Neveah plans to speak during sentencing, according to her family.
City News Service contributed to this report.