Born in Paris, Gallon was the elder brother of composer
Noël Gallon. He had a long association with the
Paris Conservatoire, first as a student, then as the director of concerts (1906-1914), and then as a faculty member from 1919 to 1949. A professor of
harmony, he taught such notable musicians as
Elsa Barraine,
Paul Bonneau,
Henri Challan,
Georges Dandelot,
Jean-Yves Daniel-Lesur,
Jeanne Demessieux,
Pierre Dervaux,
Maurice Duruflé,
Henri Dutilleux,
Ulvi Cemal Erkin,
Jean Hubeau,
Paule Maurice,
Olivier Messiaen,
Jean Rivier,
Denise Roger,
Pierre Sancan, and
Paul Tortelier. He was the choir master at the
Paris Opera from 1909 to 1914. He died in Paris in 1959.