His life story is obscure, to the point that scholar
Aharon Hyman wrote "Regarding the events of this
tanna's life, much confusion has arisen, to the point that even if we say that [the lives of] two people are [recorded in his name], we will not solve all difficulties." Hyman then performed an exhaustive investigation, concluding that seven generations of Torah scholars from one family appear in the Mishna, three of them named "Rabbi Tzadok" and three named "Rabbi Eleazar bar Zadok". Of the three named Eleazar, the first was the son of "Tzadok" (in his lifetime the title "Rabbi" was not popular, but he was occasionally known after his death as "Rabbi Tzadok"), and was the student of Rabbi Yochanan HaHorani, and worked as a shopkeeper in
Jerusalem all his life, together with Abba Shaul ben Bitnit. The second Eleazar was son of the well-known
Rabbi Zadok, and this Rabbi Eleazar provided the well-known testimonies from the house of
Rabban Gamliel and was considered one of Rabban Gamliel's greatest students. The third Eleazar - son of the third Rabbi Tzadok - was the student of
Rabbi Meir. ==In Rabban Gamliel's house==