He then went to the port of San Pedro, where he and John Temple carried on a trading business and general-merchandise store from 1844 till 1849.

The importation was a rockaway, costing $1000, along with two American horses, all coming from New England around the Horn on the customary windjammer.

In 1851, landowner Vicente de la Osa sold Rancho Providencia to Alexander and Mellus Company.

[3] His brother, George C. Alexander, and Phineas Banning operated Alexander & Banning as a successful freight and stage line,[4][5] and in 1851 they: brought in from Salt Lake ten heavy freight wagons, the first seen in this part of the country, and supplemented them later with the purchase of a whole train of 16 wagons and 168 mules from Chihuahua, at a cost of about $30,000.

[Later, in February 1855, he] was known to be an experienced frontiersman, and though they had a terrible time of it—they were three days going one mile in San Francisquito Canyon, building the road as they advanced—the train reached Fort Tejon with cargo intact.

[2]During the Mexican War of 1846–47, he favored the Americans and was made a prisoner by the Californios at the Rancho Santa Ana del Chino of Isaac Williams, but he was released on parole.

He was the first President of the Los Angeles Common Council, the governing body of the city, in 1850–51, resigning on September 25, 1851.