His brother, Eliezer Simcha Rabinowitz, was the Rabbi in Kingsbury, London; Cape Town, South Africa, Newcastle-upon-Tyne, Hull, and finally of Cheadle in Manchester.

His sister, Dr. Fanny Rabinowitz, who immigrated to Israel from London in the early 1950s, was a well known Jerusalem doctor who was influential in founding the nursing school at the Hadassah Hospital.

During World War II he was appointed Senior Jewish chaplain of the British Army; he served with Allied forces in the Middle East and during the Normandy invasion.

In 1945 Rabinowitz accepted a position as chief rabbi of the United Hebrew Congregation of Johannesburg and the Federation of Synagogues of Transvaal and the Orange Free State in South Africa.

He was a founder of the Movement for a Greater Land of Israel and opposed the Israeli withdrawal from the Sinai Peninsula as part of the Camp David Peace agreements with Egypt.