At Whitman College in Walla Walla, Washington, Benedict became interested in acting. During his freshman year, he accepted a dare to audition for the spring musical and won the lead role of Gaylord Ravenal in Show Boat. He also joined the Phi Delta Theta ΦΔΘ fraternity that year, which he credits with supporting his endeavors and encouraging his development. The next three years were filled with many more musical productions. Upon graduation, Benedict began a two-year training program under John Fernald, who had headed the Royal Academy of Dramatic Art in London for fifteen years.

At that time, he started to use the stage name 'Benedict'; supposedly, whilst searching for a catchier, less ethnic name, he agreed to the suggestion of "Benedict" by his agent, who was inspired by the actor's breakfast choice of Eggs Benedict during their early morning conversation.