Hepner was the founding conductor of the Edmonton Symphony Orchestra in 1952 and directed it for eight years. Moving to Hamilton, he served as music director of the McMaster Operatic Society 1961-7, the Hamilton Philharmonic Orchestra 1962-9, and the Hamilton Opera Company 1966-72. He guest-conducted orchestras in Canada, the US, and Europe, and taught in 1959 at the Jeunesses musicales, Weikersheim, West Germany, while on a Canada Council scholarship in Europe. Hepner also taught 1960-1 and 1970 at Queen's College of the City University of New York, and at McMaster University from 1961 until his death. He founded the McMaster Symphony Orchestra, a community orchestra with ties to the university, in 1973. The orchestra regularly collaborated with the Mohawk College Singers, founded and conducted by Hepner's wife, Patricia Rolston. In 1976, at Dundurn Castle, Hamilton, Hepner conducted the Mohawk College Opera Theatre in the first staged, orchestrally accompanied performance of Joseph Quesnel's Colas et Colinette since the 1807 revival.
The jazz saxophonist Darcy Hepner is his son.
Dimensions of Music: An Introduction to the Theory of Music (Toronto 1973, 1979)
Author Clifford Ford, Kevin James
"Harry Somers' letter to Lee Hepner," Canada Music Book 3, fall-winter 1971
Gee, Ken. 'Mac conductor bowed out to the cello,' Hamilton Spectator, 3 Nov 1979