The family of William Panas Jr. says Officer Frank Tepper was subject of nearly three dozen complaints over 16 years before he fatally shot Panas while breaking up an argument outside his home.
They argued the city of Philadelphia missed numerous warning signs in the years before the shooting.
The lawsuit was against both Tepper and the city of Philadelphia.
The jury found the city and the police department both "not responsible," so the Tepper family is responsible for the money.
Attorneys for the family say seven of the complaints against Tepper were for off-duty activities. The complaints include allegations he twice brandished guns at children.
City attorneys say Tepper wasn't acting as an officer and the city can't be held responsible for him acting like a "drunken idiot."
Tepper was convicted of murder and is serving life in prison.