Born in 1925 in Vatican City, where his father was the dean of the Pontifical Halls in the service of six popes, Labella began his professional career as an historian, journalist and documentarian. Early on, he had free access to the Apostolic Library of the Vatican where, he said, "I learned to dream back across history."
Chosen by famed producer Dino De Laurentiis to serve as an adviser on the Anthony Quinn religious epic Barabbas (1961), Labella drew on his deep knowledge of history as he began his steady ascent in the film and television business.
His 1977 NBC miniseries Jesus of Nazareth, directed by Franco Zeffirelli and starring Robert Powell, Laurence Olivier, Anne Bancroft and Christopher Plummer, was nominated for an Emmy as outstanding special drama in 1978.