The incident happened around 11 p.m. Tuesday inside the Lucky Liquor Store on Myrtle Avenue in the Bedford-Stuyvesant section.
Police say the man caught on surveillance camera punched and kicked a 61-year-old man, then took off.
Authorities are also looking for a woman caught on the camera, calling her a witness.
The suspect is described as being a white male who was last seen wearing a black jacket, black jeans and gray sneakers.
The witness is only described as being a white female with blonde hair.
Anyone with information in regards to this incident is asked to call Crime Stoppers at 1-800-577-TIPS (8477).