The officer was trying to escape a man thought to be in a drug-induced rage when "Chucky" Alexander stepped in body-slamming the attacker.
Dallas city council member Dwaine Caraway said he recommends the city formally thank Alexander at a council meeting.
Alexander said there was a time when he wouldn't have gotten involved but on this occasion he didn't hesitate to help.
The man who attacked the officer faces charges of assault.
The officer is on medical leave.