At around 6pm on 26 December 2019, 29-year-old Reece James Chilcott, also known as Reece Sullivan, entered Central Stores on Hunnyhill, Newport, and demanded cash from the tills.
During the incident, he had a knife tucked in his waistband, and made threats towards staff.
Chilcott then left the store, having stolen £365 in cash.
He admitted robbery and possession of an offensive weapon in a public place at Isle of Wight Crown Court on Thursday 1 October.
Appearing at the same court today (Monday 2 November), Chilcott, of no fixed abode, was jailed for four years and eight months.
Following the sentencing, DC Julia Parker from Newport CID said: “This was a frightening incident for shop staff who were left in fear for their safety.
“Chilcott was identified and arrested within days of this incident, and his sentence is a positive result for the community.”