Hertz was born in Rebrín/Rebrény, Kingdom of Hungary (presently part of the village of Zemplínska Široká, Slovak Republic), in 1872 and immigrated to New York City in 1884.

He stayed there until 1911, despite attempts by President Paul Kruger in 1899 to expel him for his pro-British sympathies and for advocating the removal of religious disabilities of Jews and Catholics in South Africa.

In 1913, Hertz was elected Chief Rabbi of the United Hebrew Congregations of the British Empire; he received 298 votes against 39 for Dayan Moses Hyamson.

His tenure was affected by arguments with a wide variety of people, mainly within the Jewish community; the Dictionary of National Biography describes him as a "combative Conservative".

Hertz tried both persuasion and such force as he could muster to influence them; he added to his credibility among these immigrants by persuading Rabbi Yehezkel Abramsky to become head of the London Beth Din.

"[5] Although Hertz vigorously denounced the horror of the Holocaust (at one point relating an eyewitness claim that "German soldiers in football attire entered [a] stadium [near Kiev].

[7] Hertz saw the British war effort in the noblest of terms, wishing Prime Minister Winston Churchill a happy 70th birthday in late 1944 with the message, "But for your wisdom and courage there would have been a Vichy England lying prostrate before an all-powerful Satanism that spelled slavery to the western peoples, death to Israel, and night to the sacred heritage of man.

Hertz "Imperial tour" took him 40,000 miles and to 42 Jewish communities over 11 months in South Africa, Rhodesia, Australia, New Zealand, Fiji and Canada.

[10] He began his tour in South Africa , which had a Jewish population of 66,000, on 27 October 1920 and travelled throughout the country over a period of three months, covering 5,000 miles by railway, including stops in several smaller communities as well as the Cape Town, Johannesburg and Pretoria, where he was greeted by Prime Minister Jan Smuts, followed by a trip to Bulawayo in neighbouring Rhodesia.

His travels then took him to New Zealand, with 2,500 Jews, stopped in Fiji where a few Jewish families were living, before arriving in Canada, with 125,000 Jews, on July 4, 1921 for a six-week tour that took him across Western Canada with stops in Vancouver, Calgary, Edmonton, Saskatoon, Regina and Winnipeg delivering eleven sermons and speaking at thirteen meetings as well as receptions with four Lieutenant-Governors, received by seven Mayors and visiting three provincial Premiers.

[11][12][10] After returning to England, he wrote “I had preached love and loyalty to the Empire wherever I went, and sown the seeds of Jewish idealism and spirituality in all the far-off places I had visited.” He was granted a private audience with King George V at Buckingham Palace in November to discuss his visit.

Hertz realised that this would cause problems for Jews and Christians alike in observing their Sabbaths, and mobilised worldwide religious opposition to defeat the proposal.