Mack was appointed to the principal oboe chair at the Cleveland Orchestra by George Szell in 1965; during his tenure, which lasted until 2001, he also played under music directors Lorin Maazel, Christoph von Dohnšnyi and, most recently, Franz Welser-M‹st. Since 2001, Mack served as a member of the Cleveland Orchestra board of directors.
Mack was born in Somerville, New Jersey, where he received his early musical training, studying with Bruno Labate and Marcel Tabuteau in high school. Friends urged him to study science or physics, but he was determined to continue with music, and went on to train at the Juilliard School with Harold Gomberg and with Tabuteau at the Curtis Institute of Music in Philadelphia.
His professional orchestral career began in the Sadler's Wells Ballet Orchestra in1951 and was followed by eleven seasons (from 1952-63) as first oboist with the New Orleans Symphony. He then had a brief stint with the National Symphony in Washington, D.C. Mack was also a founding member of the Plymouth Trio and a regular chamber music performer.
A renowned teacher, Mack was chairman of the woodwind division at the Cleveland Institute of Music since 1965. Many of his former students hold positions with major orchestras, including the Boston Symphony, Cleveland Orchestra and Metropolitan Opera Orchestra. He was also a faculty member of the Kent/Blossom Music program since its founding in 1968, and since 1976, he taught and performed at the John Mack Oboe Camp in North Carolina.
David Zauder, a retired member of the orchestra's trumpet section, told the Cleveland Plain Dealer, "John Mack was an icon of the Cleveland Orchestra. He touched thousands of lives with his special way of helping. He made everybody better."
According to the paper, he instructed his students both in playing and the art of reed-making. "Oboe teachers don't really know how to make reeds, and if they do, they don't like to give away their secrets or know how to express it," former student Frank Rosenwein, now with the Cleveland Orchestra, told the Plain Dealer. "[Mack] was able to express very clearly how to make reeds and musically how to best express using the unique qualities of the instrument."
The Plain Dealer writes that Mack's playing was noted for "a distinctive ripeness of sound and elegance of phrasing."
In his 1992 commencement address at the Cleveland Institute of Music, Mack said, "Art is a beacon and music happens to be our special beacon. (I wonder if there is a relationship between the words beacon and beckon?) Music most assuredly does sustain us, and beguile and nourish us. What kind of void would be in its absence? Not a pretty thought. So it falls to us to do what it is that we can do. Our contributions to the cause of music can take so many forms and go in so many directions."
According to a statement from the orchestra, the cause of death was brain cancer.