After World War II, he joined the editing department at Twentieth Century-Fox, at first helping other editors, including Barbara McLean, Robert L. Simpson, Louis R. Loeffler, James B. Clark, William H. Reynolds, and, in later years, Dorothy Spencer and Hugh S. Fowler.
Bretherton's most noted work was the editing of the film Cabaret (1972), which was directed by Bob Fosse.
In his 1972 review, Roger Greenspun gives some insight into Bretherton's achievement:... the film has a musical part and a nonmusical part (except for Miss Minnelli, none of the major characters sings), and if you add this to the juxtaposition of private lives and public history inherent in the scheme of the Berlin Stories, you come up with a structure of extraordinary mechanical complexity.
Since everything has to do with everything else and the Cabaret is always commenting on the life outside it, the film sometimes looks like an essay in significant crosscutting, or associative montage.
[2]Cabaret was listed as the 30th best-edited film of all time in a 2012 survey of members of the Motion Picture Editors Guild.