Canada has revoked his citizenship three times since 1995 but each time it has been overturned on appeal, the latest ruling being made on Thursday.
Helmut Oberlander says he was forced to act as a translator for the WWII squad.
He says he did not participate in atrocities and was conscripted.
The Supreme Court in Ottawa on Thursday ruled that the Canadian government must prove he was a willing participant in the eastern Europe death squad in order to deport him from the country.
It said that it was not prepared to hear the federal government's appeal against a lower court's ruling that the government should reconsider its decision to revoke Oberlander's citizenship.
Oberlander was born in Ukraine and became a member of a Nazi death squad, the Ek 10a, which operated behind the German army's front line in occupied eastern European territory between 1941 to 1943.
It was part of a force that killed more than two million people, many of them Jews, CTV News reported.
Oberlander insists that he was made to do translation work as a teenager and that he would have been executed if he refused to do so.
His responsibilities included finding food and cleaning boots before he later became an infantryman in the German army.
Oberlander emigrated to Canada in 1954, becoming a citizen in 1960 - but did not reveal his wartime record.
One of his lawyers said he was pleased by the Supreme Court's ruling.
"It's taken a great toll on his family. Over and over again the courts have exonerated him," Ronald Poulton told Reuters.
"It's been tiring and difficult and unnecessary and now the Supreme Court - the highest court - has told the government that's enough."
Mr Poulton argues that while Oberlander concealed his wartime service, this should not result in him losing his citizenship after living for 50 years in Canada, especially as he had neither carried out nor been complicit in war crimes.
But Jewish groups say Mr Oberlander "lied about his complicity in these atrocities and gained Canadian citizenship fraudulently".
They argue he should be "deported without further delay".
Last month a 94-year-old former guard at the Auschwitz death camp was sentenced to five years in jail in Germany. He was considered to be one of the last holocaust perpetrators to end up in the dock.
A 92-year-old man who has admitted being a former Nazi death squad member has won a court victory in Canada, fending off the latest of several efforts to revoke his citizenship.