A student of the illustrious Radbaz (Rabbi David ben Solomon ibn Abi Zimra), he is considered the last Chief Rabbi of Egypt to hold sway over the entire Jewish community in Egypt, mostly Musta'arabi Jews, after the abolition of the office of nagid, and whose halachic rulings were widespread across the land.
He was a nephew (not a son, as had been believed) of the master of the mint for the Ottoman Sultan in Cairo, Abraham de Castro.
In 1570, he visited Safed in the land of Israel, where he was the honored guest in the home of Rabbi Joseph Karo, who held him in great esteem.
[1] He describes this visit by saying that he saw Rabbi Joseph Karo practise in accordance with the first opinion that he brings down in one of the topics addressed in his seminal work, the Shulhan Arukh.
[7] He also wrote a commentary on the Tractate Betzah (Yom Ṭov), which was published post-mortem under the name Toldot Yaakov (Jerusalem 1865), a book entitled "Hilkot Nazirut", and a number of similar writings on Talmudic subjects, published by Jacob Hagis in his "Halakot Ketanot", Venice, 1704, as well as other manuscripts which were either unpublished or are no longer extant.