Gluck was born as Reba Feinsohn to a Jewish family in Bucharest, Romania, the daughter of Zara and Leon Feinsohn. Gluck moved to the United States at a young age. Although her initial success came at the Metropolitan Opera in New York City, Gluck later concertized widely in America and became an early recording artist. Her recording of “Carry Me Back to Old Virginny” for the Victor Talking Machine Co. was the first celebrity recording by a classical musician to sell one million copies. Gluck was a founder of the American Woman’s Association.
Her daughter Marcia Davenport was the child of her first marriage (to Bernard Glick, a dentist). Gluck later married violinist Efrem Zimbalist and had two children, Efrem Zimbalist, Jr. and Maria. Gluck evidently adopted her professional surname as a variation of her first husband’s surname (“Glick”).
Gluck retired to New Hartford, Connecticut to raise her family in 1925. Although by background an assimilated and nonpracticing Jew who continued to consider herself ethnically Jewish, she found herself attracted, along with her husband Efrem, to Anglican Christianity, and they regularly attended the Episcopal Church in New Hartford. Efrem Jr. and Maria were both christened there, and the couple financed Efrem through an Episcopal boarding school in New Hampshire. Efrem Jr. later became active in evangelical circles and was one of the founders of Trinity Broadcasting Network. Gluck recorded several Christian hymns in duet with Louise Homer, among them “Rock of Ages”, “Whispering Hope”, “One Sweetly Solemn Thought” and “Jesus, Lover of My Soul”.