Tradesman and junk dealer Josef Szczurek, 56, was convicted of shooting dead the widower identified only as Heinz N. in the old man's Berlin apartment in late 2006 or early 2007.
Szczurek dismembered the body and placed it into the victim's own deep freezer, then went on to fraudulently pocket the dead man's €2,000/month (about $2,500) pension for a decade.
The body was finally discovered when a neighbour reported Heinz N. as missing and police in January 2017 entered the apartment.
The case sparked public revulsion and a nationwide debate about the isolation of many elderly people, especially in big cities.
The defence denied the murder and argued the lonely widower had probably committed suicide.
Szczurek only admitted to cutting up the body and collecting the pension money, claiming it had financed his gambling addiction.
Judge Peter Schuster ruled out early parole for Szczurek before his minimum 15 years behind bars, pointing to the severity of the crime.