At 23 years old he embarked for the New World in 1839 to work for an import/export company, The Gravenhorst & Co. During the voyage, a Briton persuaded him to stay in Havana where the tobacco business was flourishing.

He achieved the qualification of "Provider of His Majesty Don Alfonso XII, King of Spain".

[2] He found the tropical climate in Cuba difficult, so he decided against a lasting stay.

His youngest brother, August Ludwig Upmann (born 1818), started to work with him and stayed in Cuba.

Hermann returned to Germany in 1848 and founded the cigar company Gebrüder Upmann & Co.