The children's home closed in the 1980s
Eugene Devoti, 79, had been found guilty of five indecent assaults against boys while working at Tennal Assessment Centre, Harborne, Birmingham, in the 1970s and '80s.
Judge Laurence Marshall said he and co-defendant Arthur Birch, 81, whose sentencing for similar offences was adjourned, had ruined the futures of young boys at the home.
The former nightwatchmen were found guilty of 15 charges at a trial in June.
Judge Marshall told Devoti: "It has been demonstrated to the court that you and Mr Birch used your positions to satisfy your perverted desires.
"You were entrusted by society, which this court represents, with the care of these children during the hours of the night.
"Many of the children who were vulnerable and came from deprived backgrounds were pre-pubescent and their introduction to sex was through abuse practised against them by you and Mr Birch."
Birch and Devoti worked in the dormitories at the Tennal Assessment Centre in Harborne in the late 1970s and early 1980s.
The trial heard from 26 men aged between 12 and 15 at the time of the offences who said the pair toured dormitories at night, plying them with cigarettes and chocolate.
Birch, a WWII veteran, was found guilty of seven indecent assaults and three counts of a serious sexual nature.
Devoti, 79, a retired music teacher, was convicted of five counts of indecent assault.
Both men denied all the charges.
Birch, of Wisley Way, Quinton, Birmingham, and Devoti, of Rising Lane, Baddesley Clinton, Warwickshire, were cleared of a total of 20 other charges against them.
The Tennal Assessment Centre, in the Harborne area of Birmingham, was home to dysfunctional and vulnerable youngsters and closed in the mid-1980s.