Ya’akov was a member of the movement from 1938 to 1946. He was the head of a group, member of the ken leadership and of the national committee. Ya’akov was sent by his movement on trips to distribute the Zionist shekel throughout Hungary. During the Holocaust he was engaged in the distribution of forged documents. In September 1944 he was arrested by the Gestapo and incarcerated for three months in the Svábhegy prison. Ya’akov was set free by the Hungarian Zionist Association’s lawyer, Dr. Beregi. After the liberation he studied at university in Budapest. He made aliya. Ya’akov did research. He emigrated to Canada and got a worldwide reputation as an atom researcher. At the age of 80 he retired as Professor at Concordia University. He resided in Toronto, Canada.