John Hoyt

John Hoyt was a former history teacher and stand-up comedian who entered films after considerable stage work with Orson Welles' Mercury Theater in the late 1930s and early 40s. A prolific character actor in over 75 movies, Hoyt often played scientists, aristocrats and assorted authority figures, as well as turning in his fair share of mad professors.

WIKIPEDIA

HOGAN'S HEROES · S3, E3

D-Day at Stalag 13

To help the Allied invasion at Normandy, Hogan convinces the Germans that Klink has been promoted to Chief of Staff.
HOGAN'S HEROES · S4, E11

Bad Day in Berlin

An American agent enters Germany and then works with Hogan's people to get a German officer out of Berlin.
HOGAN'S HEROES · S6, E1

Cuisine A La Stalag 13

LeBeau wants to escape, leaving Stalag 13 without its resident chef.
HOGAN'S HEROES · S3, E13

Evenings Of Generals

Posing as waiters, the heroes want to get rid of a room full of German generals.
HOGAN'S HEROES · S2, E30

The Reluctant Target

Klink nabs a spy, so Hogan takes the focus off his catch by making Klink think someone's trying to kill the commandant himself, leading Klink to have Hogan become a decoy commandant.