Emonte Morgan's defense accuses the state of making inflammatory statements that may have swayed the jury.
He was found guilty last month of murdering Officer French and wounding her partner.
Emonte Morgan found guilty in murder of CPD Ofc. Ella French
The jury of seven men and five women, most of whom live in the suburbs, deliberated for just over three hours before reaching their verdict.
In court, 23-year-old Morgan showed no emotion as the jury found him guilty on all counts. He did not testify in his own defense.
His brother, Eric Morgan, took a plea deal for weapons charges in the case and was sentenced to seven years in prison .
The shooting happened in Englewood after a traffic stop, as police and Emonte Morgan, who had a gun in his waistband, scuffled in the backseat of an SUV.
The jury was shown graphic police body camera video during which, at one point, Emonte Morgan is seen with a gun in his hand, stepping around both French and her partner, Carlos Yañez, who were on the ground.
SEE MORE: Surveillance video shows traffic stop before fatal shooting of CPD Officer Ella French; 2 charged
But the defense said based on the bodycam video, it is unclear what exactly happened, arguing that Morgan was trying to drop his gun when it went off during the struggle even though several shots were fired.
"This is a coverup, point blank, period. And I do believe that my son will receive justice. I will not stop. I will continue to fight for my son's justice," Evalena Flores, Morgan's mother, said as she left the courthouse.
Emonte Morgan now faces a possible life sentence.