1930: Davis represents 10 film studios in a Supreme Court case alleging Sherman Act violations in film distribution. Though the decision goes against Davis, Louis G. Mayer, head of Loew's and its MGM subsidiary, is so impressed by the firm's work that he retains Davis Polk as outside counsel.

1932-1933: The firm works to develop a more efficient mechanism for handling railroad failures and helps produce section 77 of chapter VIII of the 1933 Bankruptcy Act, which establishes the goal of getting the bankrupt company back on its feet with the cooperation of creditors and under the supervision of a trustee.

1930s: During the Depression, the firm is involved in numerous railroad reorganizations, typically representing security holders or trustees. It also represents multiple banks in matters involving corporate bankruptcies, overseas accounts and congressional investigations.

1934: S. Hazard Gillespie, who will later become a partner and senior litigator at the firm, works as one of the first summer associates.

1935: In response to the 1933 Glass-Steagall Act, which dictates the separation of banking and securities underwriting operations, the firm perform the legal work for the creation of Morgan Stanley & Co. as a separate entity from J.P. Morgan & Co.

1935: Partner F.A.O. Schwarz, working on a Morgan Stanley underwriting for AT&T's Indiana Bell, helps develop new securities offering documents to meet regulatory requirements under the Securities Act of 1933. During the Depression, Schwarz would also take a year off from the firm to run the family toy store founded by his similarly named grandfather.