[4][5] After serving as an officer in the American Expeditionary Force during World War I,[6] Gerlach became a gentleman bootlegger who operated speakeasies on behalf of gambler Arnold Rothstein in New York City.

[7] Flaunting his newfound wealth as a bootlegger in New York, Gerlach threw lavish parties,[8] never wore the same shirt twice,[9] used the phrase "old sport",[4] claimed to be educated at Oxford University,[10] and fostered outlandish myths about himself, including that he was a relation of the German Kaiser.

[17] Although he applied to be a major, he was commissioned as a first lieutenant and managed military logistics for the American Expeditionary Forces in Hoboken, New Jersey.

[17] Immediately after his discharge, Gerlach often traveled between Cuba and the United States during which time he likely became involved in illegally importing alcohol during Prohibition.

[4][5] Initially, Fitzgerald scholars were uncertain where the two met and could not find property records for a Long Island estate with Gerlach's name.

[18][19] In 2022, scholars discovered evidence that Gerlach operated a Manhattan speakeasy in 1927 in a building owned by Arnold Rothstein,[7] the gambler and kingpin of the Jewish Mob upon whom Fitzgerald based the character of Meyer Wolfsheim in his novel, The Great Gatsby.

[20][21] In a letter written to Corey Ford at MGM in 1937, Fitzgerald stated he met Rothstein in New York City in unspecified circumstances.

[22] According to a Variety magazine article dated July 27, 1927, New York police raided Gerlach's posh speakeasy located at 51 West 58th Street.

Flaunting his new wealth, Gerlach threw lavish parties,[8] never wore the same shirt twice,[9] used the phrase "old sport",[4] claimed to be educated at Oxford University,[10] and fostered myths about himself, including that he was a relation of the German Kaiser.

[5] Several years before her death, Zelda stated "that Gatsby was based on 'a neighbor named Von Guerlach or something who was said to be General Pershing's nephew and was in trouble over bootlegging'".