Dr. Otto Hanns Mankiewicz initially pursued a legal career, providing his brother-in-law, Dr. Oscar Troplowitz, with legal advice during his time as an assistant judge in Altona. In 1906, Troplowitz made him a co-shareholder of Beiersdorf & Co. As a founder member of what is now the Markenverband (German Brands Association), he particularly encouraged a brand mindset at Beiersdorf. He died seven months after Oscar Troplowitz on December 2, 1918.