[6] A few months later the Treaty of Trianon allocated greater Transylvania, including Nagysomkút, to Romania from the Kingdom of Hungary.

At Harvard, he studied under Roscoe Pound[9] and also did research for Sheldon Glueck, who at that time was writing a book on war crimes.

He returned to New York, but was recruited only a few weeks later to participate as a prosecutor (with the simulated rank of Colonel) on the legal team of Telford Taylor in the subsequent Nuremberg trials.

[citation needed] In a 2005 interview for The Washington Post, he revealed some of his activities during his period in Germany by way of showing how different military legal norms were at the time: Someone who was not there could never really grasp how unreal the situation was ...

[15]Ferencz stayed in Germany after the Nuremberg trials, together with his wife Gertrude,[8] whom he had married in New York[16] on March 31, 1946.

[10] From 1985 to 1996, Ferencz also worked as an adjunct professor of international law at Pace University at White Plains, New York.

The administration concluded a large number of bilateral agreements with other states that excluded US citizens from being brought before the ICC.

[16] In this vein, he suggested in an interview given on August 25, 2006, that not only Saddam Hussein should be tried, but also George W. Bush, because the US had begun the Iraq War without the UN Security Council's permission.

[25] On May 3, 2011, two days after the death of Osama bin Laden was reported, The New York Times published a Ferencz letter that argued that "illegal and unwarranted execution—even of suspected mass murderers—undermines democracy".

The city's Deputy Mayor Saskia Bruines (International Affairs) traveled to Washington D.C. to symbolically present the street sign to Ferencz.

[30] In 2018, Ferencz was the subject of a documentary on his life, Prosecuting Evil, by director Barry Avrich, which was made available on Netflix.

[32] On June 20, 2019, artist and sculptor Yaacov Heller honored Ferencz—presenting him with a bust he created—commemorating his extraordinary life dedicated to genocide prevention.

[38] In January 2022, Ferencz appeared as an interviewee in the German documentary Ganz normale Männer - Der "vergessene Holocaust" which was based on the book Ordinary Men - Reserve Police Battalion 101 and the Final Solution in Poland by Christopher Browning.

An English language version of the documentary was released by Netflix in September 2023 as Ordinary Men - The "Forgotten Holocaust".

[citation needed] In March 2022, an audio clip of Ferencz was played during the eleventh emergency special session of the United Nations General Assembly and he later gave an interview to BBC Radio 4's The World Tonight on the Russian invasion of Ukraine.

[52] Ferencz died at an assisted living facility in Boynton Beach, Florida, on April 7, 2023, at the age of 103.

[54] According to a 2017 interview with Lesley Stahl on 60 Minutes, Ferencz pledged to will his life savings to genocide prevention initiatives.