The Justice Department said the man, Friedrich Karl Berger, 94, was an armed guard in a subcamp of the Neuengamme concentration camp, where prisoners were held during the winter of 1945 and forced to work outdoors “to the point of exhaustion and death.”

“Berger was part of the SS machinery of oppression that kept concentration camp prisoners in atrocious conditions of confinement,” Brian A. Benczkowski, an assistant attorney general in the department’s criminal division, said in a statement on Thursday. “This ruling shows the Department’s continued commitment to obtaining a measure of justice, however late, for the victims of wartime Nazi persecution.”

A lawyer for Mr. Berger, Hugh B. Ward, did not immediately respond to messages seeking comment.

Mr. Berger, of Oak Ridge, Tenn., could not immediately be reached for comment. He told The Washington Post on Thursday that he was ordered to work in the camp, was there for a short time and did not carry a weapon. In the United States, he said, he had made a living building wire-stripping machines.

“After 75 years, this is ridiculous. I cannot believe it,” he told The Post. “You’re forcing me out of my home.”

The Justice Department said that Mr. Berger was ordered deported after a two-day trial. A federal immigration judge in Memphis, Rebecca L. Holt, found that Mr. Berger was deportable under the 1978 Holtzman Amendment to the Immigration and Nationality Act because his “willing service as an armed guard of prisoners at a concentration camp where persecution took place” constituted assistance in Nazi-sponsored persecution, the department said.

Mr. Berger served at a Neuengamme subcamp near Meppen, Germany, where Jews, Poles, Russians, Danes, Dutch, Latvians, French, Italians, and political opponents of the Nazis were imprisoned, the department said. There were about 80 Neuengamme subcamps across northern Germany.

At the end of March 1945, when the Nazis abandoned Meppen to escape advancing British and Canadian forces, Mr. Berger helped guard prisoners during their forcible evacuation to the main camp — a nearly two-week trek under inhumane conditions that claimed the lives of some 70 prisoners, the department said.

Judge Holt said that Mr. Berger acknowledged that he had never requested a transfer from concentration camp guard service and that he had continued to receive a pension from Germany based on his employment in the country, “including his wartime service.”

Efraim Zuroff, a Holocaust historian and the Simon Wiesenthal Center’s chief Nazi hunter, applauded the decision to deport Mr. Berger, saying his advanced age in no way diminished his guilt or the need to hold him accountable for his crimes.

“Especially these days, when we see anti-Semitism on the rise and the rise of right-wing movements, this is a reminder that, if you commit such crimes, even many years later, you will be held accountable,” said Mr. Zuroff, who has pursued Nazi war criminals for 40 years. “There is no expiration date on justice.”