Omar Famuyide was spotted on the website's "people you may know" feature by the victim of a knifepoint car robbery in Birmingham.
Detectives then linked him to a string of other robberies and firearms offences.
The 21-year-old, of Highgate, Birmingham, was jailed for 17 years at the city's crown court.
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He was found guilty of robbery, attempted robbery, possession of a firearm and possession of a knife after a trial.
Among his crimes, Famuyide was one of two men who forced entry into the Ambassador's Relaxation Suite in Florence Street last July.
Once inside, the men threatened women with a metal bar and a handgun, before escaping empty handed.
A month later, Famuyide stole a car at gunpoint from a man in Highgate.
The vehicle was found two days later with the handgun that was fired in the relaxation suite a month earlier, and keys to another vehicle stolen at knifepoint.
The victim of the second robbery recognised Famuyide by coincidence on Facebook, and he was later arrested.
Det Con Rhiannon Daff said the Facebook information was "a crucial part of the investigation" and "the final piece of the jigsaw."
A robber who was caught after one of his victims recognised him on Facebook has been jailed.