Dehner portrayed a number of historical figures, including the previously mentioned Pat Garrett in the 1957 film The Left Handed Gun, Jean Lafitte in the 1964 episode "The Gentleman from New Orleans" of NBC's Bonanza, Thomas Jefferson in the 1964 episode "Plague" of the anthology series The Great Adventure, Dean Acheson in the 1974 TV movie The Missiles of October, Lafayette C. Baker in the 1977 film The Lincoln Conspiracy, John Muir in the 1979 TV movie Guardian of the Wilderness (also known as Mountain Man), Henry Luce in the 1983 film The Right Stuff about the Mercury astronauts, and Admiral Ernest J. King in the 1983 television miniseries The Winds of War and the 1988 sequel War and Remembrance.