Rav Shmuel ben Yeshaya HaLevi Horowitz was born in Safed, in the Land of Israel. His father, the chief rabbi of Safed and a prominent Chabad chassid, at first fought hard against his son's turn to Breslov, but the two later reconciled, and his father supported him through a period of financial hardship.

He was drawn to Breslov chassidus after reading Reb Alter Tepliker's Hishtapchus HaNefesh, and became a disciple of Reb Avraham Sternhartz, going on to become one of the great ovdim of his generation. Based in Jerusalem, it was through him that Rabbi Shmuel Shapiro attached himself to Breslov in 1934.

In 1928 he travelled from Mandate Palestine to Uman in Soviet Ukraine. After meeting the Breslover chassidim of Poland, he crossed the border illegally and took part in three Rosh Hashanah gatherings in Uman before being caught. After months in a Soviet prison, he was released through the intervention of Rav Kook, Chief Rabbi of Mandate Palestine, and sent back to the Land of Israel.

In 1933 he wrote an account of his journey, Kuntres Yemei Shmuel, addressed to the Breslover chassidim in Poland and later expanded into a longer work. He devoted himself to printing Breslov writings: in 1935 he published the first complete edition of Reb Avraham Chazan's Biur HaLikutim, and he compiled Kuntres HaHosafos, a collection of accounts about the Baal Shem Tov, Rebbe Nachman and his followers. Works: Yemei Shmuel, Kuntres HaHosafos.

He passed away on 12 Adar 5732 (1972).