Weisbart began his career as an editor in 1942. Until his last film, A Streetcar Named Desire in 1951, he worked as an editor with in 21 productions, including several films of Michael Curtiz. With the emergence of the film Mara Maru from the year 1952, Weisbart turned to film production. As a producer he was involved in about 30 productions.
In 1967 he was involved as a producer and writer on the television series Colonel Custer.
1949 Weisbart received for his work on Silent lips a nomination for the Academy Award for Best Editing.