Rabbi Meir HaKohen, also called Maharam Katz, was born in Frankfurt to Rabbi Moshe. He is best known as the father of Rabbi Shabbatai HaKohen, the Shach.

His father sent him to Krakow to study in the yeshiva of Rabbi Meir of Lublin (the Maharam of Lublin), where he learned in chavruta with Rabbi Yehoshua Heshel, author of Meginei Shlomo. He also studied under Rabbi Yehoshua Falk Katz, the Sma. He married the daughter of Rabbi Nachum Lukover.

He was appointed av beit din of Amstibovo in the Polish-Lithuanian Commonwealth, where he became known as a leading halachic authority. Toward the end of his life he became av beit din of Mohilev on the Dnieper. He was the first teacher of his son, the future Shach, who was born in Amstibovo and began his studies with him.

For his son's great work, Siftei Kohen on the Shulchan Aruch, Yoreh De'ah, he composed a short poem that appears in the book, whose opening letters spell out his signature, "מאיר הכהן חזק". Ten or fourteen of his responsa were printed at the end of his son's Gevurat Anashim. His other children were Rabbi Yonah Nachum, av beit din of Sochaczew, and a daughter who was an ancestor of Rabbi Meir Eisenstadt, author of Panim Me'irot.

He passed away in Mohilev around 5405 (1645).