| Munroe | 1963 | Professor Hendrick Von Schmidt | TV Movie |
| The Story of Dr. Lister | 1963 | Lecture Attendee | Short Film |
| One, Two, Three | 1961 | Count von Droste Schattenburg (voice, uncredited) | Movie |
| The Errand Boy | 1961 | Baron Elston Carteblanche | Movie |
| Pete and Gladys | 1960 | Otto Bergner / Otto | TV Show |
| The Tab Hunter Show | 1960 | Hodac | TV Show |
| One Step Beyond | 1959 | Franz Schuldorf | TV Show |
| Johnny Staccato | 1959 | Otto Humboldt | TV Show |
| The Many Loves of Dobie Gillis | 1959 | Himelmayer | TV Show |
| The Untouchables | 1959 | Steve Slovic | TV Show |
| Lawman | 1958 | Hans Steinmayer | TV Show |
| The Wings of Eagles | 1957 | Manager | Movie |
| Maverick | 1957 | Klaus Jonckbloet / August Bockenheimer / Professor Kronkhite / ... | TV Show |
| The Dinah Shore Chevy Show | 1956 | Tug Captain | TV Show |
| The Gale Storm Show: Oh! Susanna | 1956 | | TV Show |
| Many Rivers to Cross | 1955 | Spectacle Man | Movie |
| Carolina Cannonball | 1955 | Stefan | Movie |
| Spy Chasers | 1955 | King Rako of Truania | Movie |
| 3 Ring Circus | 1954 | Colonel Fritz Schlitz | Movie |
| Living It Up | 1954 | Dr. Emile Egelhofer | Movie |
| The Glenn Miller Story | 1954 | Kranz | Movie |
| White Christmas | 1954 | Landlord (uncredited) | Movie |
| The Halls of Ivy | 1954 | Dr. Spatzen | TV Show |
| Willy | 1954 | Muller the Butcher | TV Show |
| Houdini | 1953 | Schultz | Movie |
| Stalag 17 | 1953 | Sgt. Johann Sebastian Schulz | Movie |
| G.E. True Theater | 1953 | Dr. Haegendorff | TV Show |
| Private Secretary | 1953 | Gregor Tiomkin | TV Show |
| Die Jungfrau auf dem Dach | 1953 | Michael O'Neill | Movie |
| Where's Raymond? | 1953 | Otto Kleinschmidt | TV Show |
| Ma and Pa Kettle on Vacation | 1952 | Cyrus Kraft | Movie |
| O. Henry's Full House | 1952 | Menkie (segment "The Gift of the Magi") (uncredited) | Movie |
| The World in His Arms | 1952 | General Ivan Vorashilov | Movie |
| I Married Joan | 1952 | Professpr Frederich Gottschalk | TV Show |
| Life with Luigi | 1952 | Schultz | TV Show |
| On the Riviera | 1951 | Gapeaux | Movie |
| Father Is a Bachelor | 1950 | Jericho Schlosser | Movie |
| Border Incident | 1949 | Hugo Wolfgang Ulrich | Movie |
| Give My Regards to Broadway | 1948 | Arthur Dinkel | Movie |
| The Emperor Waltz | 1948 | Dr. Zwieback | Movie |
| If You Knew Susie | 1948 | Count Alexis | Movie |
| Mother Wore Tights | 1947 | Papa | Movie |
| A Night in Casablanca | 1946 | Heinrich Stubel / Max Pfferman | Movie |
| Night and Day | 1946 | Wilowski | Movie |
| Faithful in My Fashion | 1946 | Professor Boris Riminoffsky | Movie |
| A Royal Scandal | 1945 | Gen. Ronsky | Movie |
| The Dolly Sisters | 1945 | Ignatz Tsimmis | Movie |
| She Went to the Races | 1945 | Dr. Gurke | Movie |
| Men in Her Diary | 1945 | Mme. Irene | Movie |
| House of Frankenstein | 1944 | Hussman | Movie |
| It Happened Tomorrow | 1944 | Mr. Beckstein | Movie |
| Summer Storm | 1944 | Kuzma (as Sig Rumann) | Movie |
| The Hitler Gang | 1944 | General von Hindenburg | Movie |
| Government Girl | 1943 | Ambassador | Movie |
| Sweet Rosie O'Grady | 1943 | Joe Flugelman | Movie |
| Tarzan Triumphs | 1943 | German Sergeant (as Sig Rumann) | Movie |
| The Song of Bernadette | 1943 | Louis Bouriette | Movie |
| They Came to Blow Up America | 1943 | Dr. Herman Holger | Movie |
| China Girl | 1942 | Jarubi | Movie |
| Crossroads | 1942 | Dr. Alex Dubroc | Movie |
| Desperate Journey | 1942 | Preuss | Movie |
| Remember Pearl Harbor | 1942 | Dirk Van Hoorten | Movie |
| To Be or Not to Be | 1942 | Colonel Ehrhardt | Movie |
| Berlin Correspondent | 1942 | Dr. Dietrich | Movie |
| Enemy Agents Meet Ellery Queen | 1942 | Heinrich - Spy Leader | Movie |
| Love Crazy | 1941 | Dr. Wuthering (as Sig Rumann) | Movie |
| Shining Victory | 1941 | Professor Herman Von Reiter | Movie |
| So Ends Our Night | 1941 | Ammers (as Sig Rumann) | Movie |
| That Uncertain Feeling | 1941 | Kafka (as Sig Rumann) | Movie |
| The Wagons Roll at Night | 1941 | Hoffman the Great (as Sig Rumann) | Movie |
| The Man Who Lost Himself | 1941 | Dr. Simms (as Sig Rumann) | Movie |
| This Woman Is Mine | 1941 | John Jacob Astor | Movie |
| World Premiere | 1941 | Franz von Bushmaster (as Sig Rumann) | Movie |
| Bitter Sweet | 1940 | Herr Schlick (as Sig Rumann) | Movie |
| Comrade X | 1940 | Emil Von Hofer (as Sig Rumann) | Movie |
| Dr. Ehrlich's Magic Bullet | 1940 | Dr. Hans Wolfert (as Sig Rumann) | Movie |
| Four Sons | 1940 | Newmann (as Sig Rumann) | Movie |
| I Was an Adventuress | 1940 | Herr Protz (as Sig Rumann) | Movie |
| Victory | 1940 | Mr. Schomberg | Movie |
| Outside the Three-Mile Limit | 1940 | Van Cleve | Movie |
| Confessions of a Nazi Spy | 1939 | Dr. Julius Gustav Krogman (as Sig Rumann) | Movie |
| Honolulu | 1939 | Psychiatrist (as Sig Rumann) | Movie |
| Never Say Die | 1939 | Poppa Ingleborg (as Sig Rumann) | Movie |
| Ninotchka | 1939 | Iranoff (as Sig Rumann) | Movie |
| Only Angels Have Wings | 1939 | Dutchy (as Sig Rumann) | Movie |
| Remember? | 1939 | Dr. Schmidt (as Sig Rumann) | Movie |
| Girls on Probation | 1938 | Roger Heath (as Sig Rumann) | Movie |
| Suez | 1938 | Sergeant Pellerin (as Sig Rumann) | Movie |
| The Great Waltz | 1938 | Wertheimer (as Sig Rumann) | Movie |
| The Saint in New York | 1938 | Hutch Rellin (as Sig Rumann) | Movie |
| Paradise for Three | 1938 | Mr. Bold (as Sig Rumann) | Movie |
| I'll Give a Million | 1938 | Anatole Primerose | Movie |
| A Day at the Races | 1937 | Dr. Steinberg (as Sig Rumann) | Movie |
| Heidi | 1937 | Police Captain (as Sig Rumann) | Movie |
| Maytime | 1937 | Fanchon (as Sig Rumann) | Movie |
| Nothing Sacred | 1937 | Dr. Emil Eggelhoffer (as Sig Rumann) | Movie |
| On the Avenue | 1937 | Herr Hanfstangel (as Sig Rumann) | Movie |
| Seventh Heaven | 1937 | Durand (as Sig Rumann) | Movie |
| Thank You, Mr. Moto | 1937 | Colonel Tchernov (as Sig Rumann) | Movie |
| Thin Ice | 1937 | Prime Minister Ulricht (as Sig Rumann) | Movie |
| Think Fast, Mr. Moto | 1937 | Nicolas Marloff (as Sig Rumann) | Movie |
| This Is My Affair | 1937 | Gus (as Sig Rumann) | Movie |
| Lancer Spy | 1937 | Lt. Col. Gottfried Hollen | Movie |
| Midnight Taxi | 1937 | John B. Rudd | Movie |
| The Great Hospital Mystery | 1937 | Dr. Taggert (as Sig Rumann) | Movie |
| Love Under Fire | 1937 | General Montero | Movie |
| The Bold Caballero | 1936 | Commandante Sebastian Golle (as Sig Rumann) | Movie |
| The Princess Comes Across | 1936 | Steindorf (as Sig Rumann) | Movie |
| A Night at the Opera | 1935 | Herman Gottlieb (as Siegfried Rumann) | Movie |
| The Farmer Takes a Wife | 1935 | Blacksmith (as Siegfried Rumann) | Movie |
| The Wedding Night | 1935 | Mr. Jan Novak (as Siegfried Rumann) | Movie |
| East of Java | 1935 | Hans Muller (as Siegfried Rumann) | Movie |
| Under Pressure | 1935 | Doctor (as Siegfried Rumann) | Movie |
| Spring Tonic | 1935 | Matt Conklin | Movie |
| Marie Galante | 1934 | Brogard (as Sigfried Rumann) | Movie |
| The World Moves On | 1934 | Baron von Gerhardt (as Siegfried Rumann) | Movie |
| Servants' Entrance | 1934 | Hans Hansen (as Siegfried Rumann) | Movie |
| All Quiet on the Western Front | 1930 | Mr. Meyer (uncredited) | Movie |
| Die Königsloge | 1929 | Bailiff (as Siegfried Rumann) | Movie |
| Lucky Boy | 1929 | Bridge Player (uncredited) | Movie |
