The panel deliberated for less than three hours before deciding that Nassau County detective Karl Snelders used excessive force to capture Thomas Hartmann in 2004.
Hartmann was wanted for allegedly making a harassing phone call to his wife.
He was trying to run away when the detective ran him down from behind, crushing his legs.
Snelders said he did it because he thought the former construction worker had a gun.
The jury ruled that the detective acted with an evil motive and callous disregard for Hartmann's rights.
An attorney for the county had no comment.