Young targeted convenience stores and threatened staff with a firearm in each of his armed raids. He took about £4,000 in cash over the five robberies, police said.
Detective Sergeant Scott Chimes said: "I would like to thank the victims and witnesses for the courage they displayed in assisting in this protracted investigation.
"Young has never personally showed any remorse for the frightening crimes he committed during December 2011 to January 2012.
"The sentence passed by Recorder Laird QC sends out a clear deterrent message to those considering committing similar offences.
"I would like to assure businesses and the public within London that the Metropolitan Police Flying Squad will continue to seek out and arrest those engaged in such serious crimes and bring them to justice".