Career
He is one of the tannaim whose teachings are quoted in the Mishnah. The name "HaSandlar" may imply that Rabbi Yohanan earned his living as a shoemaker, but it could also indicate that he was a native of Alexandria, Egypt. Rabbi Yochanan was a great-grandson of Rabbi Gamaliel the Elder.
He also purportedly traced his ancestry back to King David.
Rashi, the great medieval commentator, was a 33rd-generation descendant of Rabbi Yochanan. He is well known for his saying in the Mishnah of Pirkei Avoth (4:14): "Every assembly that is for the sake of Heaven will survive.
But if it is not for the sake of Heaven, it will not survive."
He died on the 29th day of the Hebrew month of Tammuz (the same yahrzeit as that of Rashi), and was buried 200 meters from the tomb of Shimon bar Yochai in Meron, Israel.