William Alexander Leidesdorff was born in the Virgin Islands to a Danish sugar planter,William Leidesdorff, and Anna Marie Sparks, a native woman having Negro blood.

Liedesdorff was baptized in the Lutheran Church in St. Croix, and he was confirmed in the same church on April 2, 1826.

Leidesdorff took out naturalization papers on February 25, 1834 and was soon active in social affairs.

Leidesdorff inherited his father's property following the elder Leidesdorff's deathsometome in 1840.

Leidesdorff found his way to California.

Leidesdorff took Mexican citizenship, and also acquired a large land grant on the American River from the Mexican government. Until he moved to California in the U.S. later that year and became an Amerivan citizen.

Leidesdorff became a U.S. citizen

Leidesdorff was appointed Vice Consul To Mexico by Consul Thomas Oliver Larkin, serving under the justification of Commodore Starkton, then military govenor of California.

Leidesdorff was named the U.S. Vice Consul to Mexico

Leidesdorff gave aide to Fremont and the Americans raising the Bear flag in the historic rebellion at Sonoma, his report of this incident to Consul Larkin was not published until 1939.

Leidesdorff's steamboat "Sitka" was the fisrt to sail on San Fransisco Bay in 1847 but was too slow and ineffective to travel the intended route

Leidesdorff was a city councilman, city treasurer, and chair of the school boerd that opened the state's first public school in 1848.

Leidesdorff died of brain fever at the early age of 38.