Born in New York, Morris Barash sang as a boy in the cantorial choirs of the legendary Zeidl Rovner and in the Schola Cantorum in his twenties. He attended the New School for Social Research and New York University and studied composition with Roger Sessions and Wallingford Riegger. He also organized synagogue choirs of his own, first for orthodox congregations and then for Reform and Conservative ones.
In 1955 Barash joined the faculty of the recently opened School of Sacred Music at the Hebrew Union College-Jewish Institute of Religion. Many of his compositions rooted in traditional hazzanut remain in manuscript, but some of his more contemporary settings for mixed choir with instrumental accompaniment were published, such as his engaging marriage service. Like his brother Jack, he developed special skills for accompanying cantorial concert renditions, and he was the pianist for many celebrated cantors of the time.