William Howard assaulted an assistant working at the Co-operative store in High Street, Eyemouth, on June 29 last year breaking a plastic screen and reaching into the till and stealing £138 in cash.
He then assaulted a female customer who struck her head on shelving to her injury and then pushed a 62-year-old woman to the floor and she struck her head to her severe injury.
Howard then stole a motor vehicle outside the shop before driving off.
He pleaded guilty to three charges at Jedburgh Sheriff Court.
Howard of Swadlincote, South Derbyshire, had already been on remand for a lengthy period.
Sentence was deferred until May 8, 2023.