Bruce Chipunza threatened two members of staff at the Saffron Building Society branch in Culver Street West, Colchester, on 1 July 2019.
Chipunza, who was armed with a screwdriver, ran off but detectives scoured CCTV footage from around the town centre.
It showed him entering a hotel where he changed his clothing, then took a taxi to where he was staying in Ellis Road, Clacton.
Further footage showed him leaving the address in another set of clothes, before heading to Westfield shopping centre in Stratford where he embarked on a shopping spree.
He used a cloned mobile phone in an attempt to conceal his movements but was arrested when he returned to Clacton the following day.
Chipunza refused to answer any questions and was charged.
He denied the offence on 16 August that year and stood trial at Chelmsford Crown Court on 11 November this year.
Following the two-week trial, he was convicted by a jury on Monday 23 November and jailed the same day.
He was sentenced to eight years for the Colchester robbery and a similar robbery he committed in Chadwell Heath, north east London, just days before on 27 June 2019.
The court heard Chipunza, 31, had 21 previous convictions for 45 offences including theft, burglary, and fraud.
We thank the authorities for their swift and effective action to detain the thief and protect the people of Essex.
We at Saffron Building Society are pleased with the outcome and that the perpetrator was handed an appropriate sentence for his crime.
We take security at our branches very seriously and thanks to safety and security procedures we have in place, no staff or members of the public were harmed in the incident.”
Spokesman for the Saffron Building Society
Investigating officer Detective Constable Tim Harris said: “Chipunza is a persistent career criminal who showed no remorse for his crimes.
“During the trial, he heard the evidence from his victims, some of whom have been left with life changing psychological trauma.
“We have supported them throughout the investigation and trial, and I commend them for their courage in facing him and giving evidence in court.
“Bringing him to justice has been a joint effort between Essex Police, Metropolitan Police Flying Squad and the Crown Prosecution Service.
“Detectives and evidential specialists worked diligently to piece together the overwhelming evidence linking Chipunza to both robberies.
“We hope his victims feel safer in the knowledge that he is now behind bars.”