Paul Isenberg (April 15, 1837 – January 16, 1903) was a German businessman who developed the sugarcane business in the Kingdom of Hawaii.

Paul Heinrich Friedrich Carl Isenberg was born April 15, 1837, in Dransfeld, Kingdom of Hanover, Germany.

The plantation was founded by diplomat Henry A. Peirce, but struggled to make a profit until Rice built an irrigation system.

During World War I, Hackfeld & Company was seized by the U.S. government Alien Property Custodian along with other assets owned by Germans.

A 1920 lawsuit argued the price was below market value, and some former stockholders including John Carl Isenberg recovered some damages.

[13] In 1887 his younger brother Johannes Friedrich Wilhelm "Hans" Isenberg (1855–1918) was brought in to be pastor of the first Lutheran church on the island for the immigrants who starting arriving in 1881.

[14] Hans had married his own niece, Paul's first child, Mary Dorothea Rice Isenberg, known as Dora, in 1883.