According to biographer Joe Adamson, when Tex was working on the cartoon A Wild Hare (1940) (which is the first official Bugs Bunny cartoon), they were looking for something for the rabbit to say when Elmer Fudd pointed his gun to the rabbit's head, Tex, off of the top of his head, said, "How about 'What's up doc?' " He used "doc" on many of his other cartoons before this, but nobody seemed to notice. "Doc" was an expression used at North Dallas High School, which Tex attended, by many students.
In addition to his role as supervising director, he also added his voice to several cartoons, for example playing Santa Claus in Who Killed Who? (1943) and lending his distinctive laugh to the bulldog in Bad Luck Blackie (1949).
Was accidentally blinded in the left eye by Charles Hastings during a rubber-band propelled paper clip fight at Walter Lantz Studios. Because of this, he had no depth perception.