Ritter's first movie role was in Miracle on 34th Street (1947). She made a memorable impression in a brief uncredited part, as a frustrated mother unable to find the toy that Kris Kringle has promised her son. Her third role, in writer-director Joseph L. Mankiewicz's A Letter to Three Wives (1949), left a mark, although Ritter was again uncredited. Mankiewicz kept Ritter in mind, and cast her as Birdie Coonan in All About Eve (1950), which earned her an Oscar nomination. A second nomination followed for her work in the Mitch Leisen ensemble screwball comedy The Mating Season (1951) starring Gene Tierney and John Lund. She enjoyed steady film work for the next dozen years.
