It happened at the Kangaroo Express in the 900 block of W. Grantham St. just after 3 a.m.
Investigators said a man came into the business and showed a gun to a female clerk. A customer saw the robbery taking place and shot the man once.
The alleged robber was taken to Wayne Memorial and then flown to Vidant Medical Center in Greenville.
Police said they were trying to identify the man and the investigation continues.
Anyone with information is asked to call the Goldsboro Police Department at (919) 580-4212 or Crime Stoppers at (919) 735-2255.