Mathew Shinto said Lee Anderson, Conservative MP for Ashfield, got between him and his attacker during the incident at The Local Choice, on Outram Street.
Mr Shinto said the theft and attack happened on Friday, September 8, during the busiest time of the day, leaving many regular customers “scared”.
The business owner, who also owns the nearby New Cross pub, said he was “shocked by the theft and punch”.
He said: “The incident turned more violent and with several youths hanging around, Lee came to my rescue.
“He put himself between my attacker and me. He made sure I was safe and that no more punches could land.
“He stayed with me until the police arrived and made a statement for me. Thanks Lee for helping me out.”
The shopkeeper said the incident runs “far deeper than the money lost” from stolen items and felt the incident was about “principles” and “the way we live” as part of a community, especially with how “challenging” it can be for families facing rising costs.
He said a suspect was identified shortly after he shared CCTV footage of the alleged attacker on social media.
Mr Anderson, deputy chairman of the Conservative Party, said: “As I ran up to Mathew, I noticed a gathering of youths who were just watching.
“The shoplifter punched Mathew as I got closer. I got between Mathew and the shoplifter to prevent him hitting Mathew again.
“The shoplifter kept hurling abuse towards Mathew. I stayed with Mathew until the police arrived and made a statement.”
Mr Anderson shared an update about the incident with his 40,000 Facebook following.
Commenting on www.fb.com/LeeAndersoninAshfieldEastwood, Janice Turton said: “While you should be commended for this, you should be careful.
“They could have took a pop at you , with very bad consequences.”
Angela Brailsford said: “Well bone Lee.”
Inspector Jon Hewitt, district commander for Ashfield, said: “We are investigating reports of a theft and an assault in Outram Street, Sutton-in-Ashfield, at around 4.50pm on Friday, September 8 and would like to hear from any additional witnesses who have yet to come forward.
“This kind of behaviour is utterly unacceptable and we are working to catch up with the person responsible.”
Anyone with information is asked to call 101 quoting incident 569 of September 8 2023.