Beginning in 1963 he became involved (initially on a part-time basis) with Yeshiva University in New York, and was integral in the founding of its Sephardic Studies Program.

Rabbi Gaon's overseas activities were controversial with some members of his London congregation, and he left under difficult circumstances.

In 1968 Rabbi Gaon delivered the main address at the dedication of the first synagogue consecrated in Spain since the Expulsion of the Jews in 1492.

He was the principal representative of the Sephardic people at the March 31, 1992 event at the Beth Yaacov synagogue in Madrid, during which King Juan Carlos of Spain revoked the 1492 Edict of Expulsion.

Haham Rabbi Gaon received Spain's Prince of Asturias Award in 1992 for his lifetime of efforts seeking a renewal of relationships between and among the Sephardim and the Spanish people.