Waltz is a man of average height and build, with short blond hair. He is only ever seen wearing the standard Military Police uniform.
Waltz appears to be a man lacking in initiative. When faced with a situation that requires action, such as Eren Jaeger's outburst during his trial, Waltz proved too unnerved to do anything until after receiving orders from Nile. He is similarly left dumbfounded in Stohess District after learning that the soldier he has been guarding is not actually Eren, and is left waiting for orders on how to act from Nile.
Waltz attends the trial of Eren Jaeger with Nile Dawk. Nile remarks on how the commoners are a rash lot for thinking of Eren as a savior, and Waltz comments that it might trigger a revolt against the central powers.
After the Scout Regiment is forced to hand Eren over to the Military Police due to their failure during the 57th Exterior Scouting Mission, Waltz is one of the soldiers tasked with guarding Eren while he is being transported. When two Titans suddenly appear inside Stohess, Waltz attempts to stop his captive from exiting his carriage only to realize that he is a decoy.