Biography
Walter Andrew Brennan (July 25, 1894 – September 21, 1974) was an American actor and singer. He won the Academy Award for Best Supporting Actor for his performances in Come and Get It (1936), Kentucky (1938), and The Westerner (1940), making him one of only three male actors to win three Academy Awards. Brennan was also nominated for his performance in Sergeant York (1941). Other noteworthy performances were in To Have and Have Not (1944), My Darling Clementine (1946), Red River (1948), and Rio Bravo (1959). Description above from the Wikipedia article Walter Brennan, licensed under CC-BY-SA, full list of contributors on Wikipedia.
Known For

Rio Bravo
Stumpy

Bride of Frankenstein
Peasant (uncredited)

Red River
'Groot' Nadine

The Invisible Man
Bicycle Owner (uncredited)

How the West Was Won
Col. Jeb Hawkins

My Darling Clementine
Old Man Clanton

Meet John Doe
The Colonel

Bad Day at Black Rock
Doc T.R. Velie Jr.

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Pa Danby

The North Star
Karp