He was also founder of the Simpson family in Chile, initiator of the first hydrographic works in the country, senator and diplomat.

[1] By 1821, Simpson was already a second lieutenant in the Chilean Navy, and in the same year during the Peruvian War of Independence he participated in the capture of the Spanish ships Resolución, San Fernando and Milagro in Callao, being promoted to captain on 7 October 1821.

Admiral Cochrane gave Simpson command of the Araucano, ordered him to Acapulco to harass Spanish shipping, and from there move on to California to purchase supplies.

Later, he cruised the Peruvian coast and was in charge of disturbing their commerce, and captured the Confederación, taking its command.

Nonetheless, the defeat of the Confederate fleet at Casma by the smaller Chilean squadron left Chile in absolute control of the southeastern Pacific Ocean.

In 1853, he became a rear admiral and continued his naval career until 1871, when he retired after 53 years in the Chilean Navy.