I have been working on an in-depth cast list:
Max Von Sydow as Jesus and the Prologue Narrator
Dorothy McGuire and Robert Loggia as Mary and Joseph
Charlton Heston as John the Baptist
Donald Pleasence as Satan
The Twelve Disciples: David McCallum as Judas, Gary Raymond as Simon Peter, Roddy McDowall as Matthew, Michael Anderson Jr. as James the Lesser, John Crawford as John, Burt Brinckerhoff as Andrew, Robert Blake as Simon the Zealot, Jamie Farr as Thaddeus, David Hedison as Philip, David Sheiner as James the Greater, Tom Reese as Thomas, and Peter Mann as Nathanael
Claude Rains as Herod the Great, Jose Ferrer as Herod Antipas, Dal Jenkins and Joseph V. Perry as Princes Philip and Archelaus, Marian Seldes as Herodias, ?? as Salome, Rodolfo Acosta as Herod the Great's Commander/Captain of Lancers, Michael Ansara as Herod Antipas' Commander, Harold J. Stone as Gen. Varus (ambassador to Antipas early in the film), John Abbott and Phillip Coolidge as Aben and Chuza (advisors to both Herods), and Jay C. Flippen and Victor Lundin as featured Centurions in Herod A.'s court. The Inbal Dance Tribe of Israel play Herod's dancers.
Telly Savalas as Pilate, Angela Lansbury as his Wife (Claudia), Paul Stewart as Questor (Herod's grim-faced commander), and Johnny Seven as Pilate's elderly aide, Richard Conte as Barabbas, the prisoner who was freed
Martin Landau as High Priest Caiaphas, Joseph Schildkraut and Abraham Sofaer as Nicodemus and Joseph of Arimathea (allies of Jesus), Victor Buono as Priest Sorak, Ron Whelan as Priest Annas, John Crawford as Priest Alexander (I believe), and Nehemiah Persoff as Shemiah (High Priest in the beginning and then the old man who is always sitting and is ignored by Caiaphas for the rest of the film). Russell Johnson plays a Scribe at Capernaum, although he only has one line. John Lupton plays a speaker there who Jesus corrects, and may have played Russell's associate who also only has one line. Chet Stratton plays Theophilus, who I believe is the other major priest in the film.
Robert Busch plays an Emissary, which fits the bill for many characters. He is often listed with the Jewish leaders in cast lists from the time.
Michael Tolan as Lazarus, Ina Balin and Janet Margolin as Mary and Martha, Van Heflin as their friend Bar Amand, Ed Wynn as the Old Blind Man Aram, Sal Mineo as Uriah the Cripple, Joanna Dunham as Mary Magdalene, Frank DeKova as her Tormentor, Sidney Poitier as Simon of Cyrene (who helps Jesus bear the cross), Kyle Johnson as one of his two sons (who I can't identify in the film), Shelley Winters as a Woman who is healed, Carroll Baker as Veronica (the woman who wipes the face of Jesus), John Wayne as the Centurion at the cross, Pat Boone as the Angel at the Tomb
The Wise Men: Cyril Delevanti as Melchior, Mark Lenard as Balthazar, and David Sheiner as Caspar who is not a friendly ghost.
Joseph Sirola plays Dumah. I'm not sure who he is. I think he might be the man Pilate tells to "get out." However, he might be the "Emissary."
Unbilled: Richard Bakalyan as the Good Thief, Marc Cavell as the Bad Thief, Felix Locher as an Old Man in Capernaum who touches Jesus, Celia Lovsky as the Elderly Woman behind the gate before the crucifixion, Leonard Mudie plays an elderly man defending Jesus in that scene, Mickey Simpson plays the most featured supporter of Barabbas, Dorothy Neumann plays the woman who says "God deliver him now," John Pickard plays Peter's Accuser, and Gil Perkins plays one of the featured Bethlehem villagers (named Jacob), which one I know not.
And Gene Roth and Kay Hammond show up too, but I'm not sure where. Renata Vanni plays a weeping woman. Also there, but less recognizable, are Nedson Booth, Norm Taylor, and Harry Wilson. I have no idea where these people are.
A helpful source: http://trekkerscrapbook.com/tag/the-greatest-story-ever-told/
Any further help with who is who (especially those who I was unsure on or couldn't identify) and any other characters (Bethlehem villagers, shepherds, other Roman soldier who have brief lines, people shouting for Jesus/Barabbas, or any others).
(Sorry about the ridiculous length)