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| Año | Título | Personaje | Valoración |
|---|---|---|---|
| 1940 | El forastero | Leon Beauregard (uncredited) | ★★★★☆ |
| 1939 | Arizona | Barfly (uncredited) | ★★★★☆ |
| 1939 | Unión Pacífico | (uncredited) | ★★★☆☆ |
| 1938 | El vaquero y la dama | Party Guest (uncredited) | ★★★☆☆ |
| 1937 | The Cherokee Strip | Town Carpenter | ★★★☆☆ |
| 1935 | It's A Small World | Snake Brown, Sr. | ★★☆☆☆ |
| 1933 | Fargo Express | Posse Rider | ☆☆☆☆☆ |
| 1932 | Lawless Valley | Rustler | ★☆☆☆☆ |
| 1932 | Beyond the Rockies | Watches Barroom Fight (uncredited) | ★★★☆☆ |
| 1932 | Ride Him, Cowboy | Townsman (uncredited) | ★★☆☆☆ |
| 1931 | Sundown Trail | Ranch Hand Goober | ★★★★☆ |
| 1925 | Ridin' Pretty | Gloom (as Bill Gillis) | ☆☆☆☆☆ |
| 1925 | Straight Through | Sheriff | ☆☆☆☆☆ |
| 1921 | Conflict | Hasdrubel Ginger | ☆☆☆☆☆ |
| 1921 | Riding with Death | Captain Jack Hughes | ☆☆☆☆☆ |
| 1920 | The Last Straw | Two Bits | ☆☆☆☆☆ |
| 1920 | Ruth of the Rockies | Pendleton Pete | ☆☆☆☆☆ |
| 1919 | His Majesty, the American | Undetermined Role | ★★★☆☆ |
Películas destacadas de William Gillis
Estas son las películas más destacadas en las que ha trabajdo:
