Rabbi Brus was born in Sawin, Poland, to a family of Trisker Hasidim.
At the age of 16, after having studied in the Yeshiva in Pinsk from the age of 11, Shaul Brus was accepted into the Knesses Beis Yitzchak yeshiva of Rabbi Boruch Ber Leibowitz in Kaminetz.
He was exiled to Siberia during the Holocaust and eventually found refuge in America, where he became a Talmudic lecturer at Yeshiva Beis HaTalmud in Bensonhurst, Brooklyn.
Brus wrote several volumes of Minchas Shaul (Hebrew: מנחת שאול) on various tractates of the Talmud.
Some of his Talmudic lectures have been posthumously printed by his children and students.