Mendlowitz was born in Világ, in the Austria-Hungarian Empire, a small town near the border of Poland, to a Hasidic family: Moshe and Bas-Sheva Mendlowitz. Shraga Feivel pronounced his family name Mendelovich. His mother died when he was ten. He was twelve when the family relocated to Mezőlaborc, where he studied "with Reb Aaron, dayyan of Mezo-Laboretz, who considered him his top pupil." Having received semicha at age 17, he continued his studies under Rabbi Simcha Bunim Schreiber. Throughout his life, however, he refused to use the title of Rabbi and insisted on being referred to as "Mr. Mendlowitz." At age 22, he "married his step-mother's younger sister, Bluma Rachel." in the town of Humenné, Slovakia, and began to study several not well known Jewish writings, including the works of Rabbi Samson Raphael Hirsch; this briefly led to controversy until he could prove the relevance of Hirsch's work in defending the Orthodox viewpoint against attempts at reforming Jewish practice.
Activities
He actively sought positions in Germany and the United States, with the intention of disseminating knowledge of Judaism to Jews previously unexposed to their heritage, and in September 1913, he arrived alone in Philadelphia. He lived in Scranton, Pennsylvania, for seven years, teaching in the local Talmud Torah. In 1920 he was able to bring his family from Hungary, and settled in Williamsburg, Brooklyn. Reb Shraga Feivel joined forces with ChazanYossele Rosenblatt in 1923, to produce Dos Yiddishe Licht, a short-lived English and Yiddish language weekly that included articles of comment and inspiration. It eventually became a daily but was forced to discontinue publication in 1927, because of financial difficulties. In fact, Chazan Rosenblatt went on a year-long concert tour to pay back the monies owed to creditors. The founding members of the yeshiva Torah Vodaath soon offered him the principalship of the institution. Originally starting off as an elementary school, Rabbi Shraga Feivel soon added the second Yeshiva high school in America. The yeshiva opened its mesivta in 1926 and then under Rabbi Mendlowitz' direction, another early development in America, a post-graduate program. Rabbi Mendlowitz first appointed Rabbi Gedalia Schorr to the faculty of the Yeshiva, later to become its principal and Rosh Yeshiva. Despite his devotion to Torah Vodaath he assisted in the founding of several similar institutions, such as Mesivta Chaim Berlin, Telshe Cleveland and Beis Medrash Gevoha. All grew to occupy important places in 20th century American Orthodoxy. His work in Jewish education extended to several other organisations he founded. Aish Dos was a specialized institution that focused on teaching outreach skills, Torah U'mesora was a nationwide umbrella organization for Jewish day schools, and Beis Medrash Elyon was one of America's first post-graduate yeshivas. In 1931 he founded Camp Mesivta, the first yeshiva day camp. Mendelowitz renounced eating meat after the Holocaust, saying: "There has been enough killing in the world."