Several men were walking down the rear lane of Disraeli Street, Blyth, at 8.50pm last Friday, when one of them walked over a parked car, causing minor damage.
The car owner, a 46-year-old man, ran after him and challenged him on Salisbury Street. He was punched several times to the head before the men all ran off.
Police have released CCTV images of a man they need to speak to who it's believed may be able to help with inquiries.
Anyone who recognises the men in the image is asked to contact police on 101, quoting reference 1243 09/09/16 or to contact Crimestoppers anonymously on 0800 555111.