He was orphaned at an early age, his father, Captain John Sloat, having been mistakenly shot and killed by one of his sentries two months before he was born,[3] and his mother dying a few years later.

Sloat then commanded the schooner Grampus during which he fought the March 1825 naval campaign against the pirate ship of Roberto Cofresí.

[4] In 1844 Sloat was appointed to command the Pacific Squadron, and in 1845, as tensions with Mexico grew, he was instructed to land in Alta California and claim it for the United States if war broke out.

Receiving a report of fighting on the Texas border while off Mazatlán, he raced north (the British were reportedly interested in California too), engaged in a skirmish called the Battle of Monterey, raised the flag over the Customs House at Monterey on July 7, 1846, and issued a proclamation announcing that California was now part of the United States.

Knickerbocker Commodore: The Life and Times of John Drake Sloat, 1781-1867 by Bruce A. Castleman, 2016, State University of New York Press https://sites.rootsweb.com/~mdannear/firstfam/watkins.htm[permanent dead link‍]